Who is eligible to open a Solo 401(k)?

A self-employed individual or owner-only business may establish a Solo 401(k) when the business has no common-law employees who meet the plan's eligibility requirements, other than the owner's spouse. Eligibility depends on the business structure, earned compensation, employee status, and terms of the plan document.

What are the Solo 401(k) contribution limits for 2026?

For 2026, an owner may make employee elective deferrals of up to $24,500, subject to compensation and the combined individual deferral limit across applicable plans. Total employee and employer contributions are generally limited to the lesser of 100% of eligible compensation or $72,000, excluding catch-up contributions. Participants age 50 or older may contribute an additional $8,000, for a potential total of $80,000. Eligible participants ages 60 through 63 may use the higher $11,250 catch-up contribution instead, for a potential total of $83,250. Special contribution calculations apply to self-employed individuals.

Can I make both pre-tax and Roth contributions to a Solo 401(k)?

Yes, when permitted by the plan document. Employee elective deferrals may be made as traditional pre-tax contributions, designated Roth after-tax contributions, or a combination of both. The combined contributions remain subject to the same annual employee elective-deferral limit.

What investment options are available in a Solo 401(k)?

Available investments depend on the Solo 401(k) plan document, trustee, custodian, and investment platform. IRA Club SBS supports integration with iFlip for AI-powered investing and may support permitted alternative investments such as real estate, private equity, precious metals, cryptocurrency, tax liens, and private loans. IRA Club SBS does not provide investment or structuring advice, make investment recommendations, or perform due diligence for account holders.

Can I take a loan from my Solo 401(k)?

A Solo 401(k) may permit participant loans when loan provisions are included in the plan document. The maximum loan is generally the lesser of 50% of the participant's vested account balance or $50,000. Loan repayment and other requirements must be followed to prevent the outstanding amount from being treated as a taxable distribution.

How do I set up a Solo 401(k) for my business?

To establish a Solo 401(k), the business adopts a written plan document, selects a trustee or plan provider, opens the plan account, and completes the required employer and participant documentation. IRA Club SBS onboarding specialists can assist with plan design, account setup, contribution options, and administrative requirements.

What are the tax benefits of a Solo 401(k) for self-employed individuals?

Traditional employee elective deferrals are generally made on a pre-tax basis, while eligible employer contributions may generally be deductible subject to applicable limits. Designated Roth contributions are made after tax, and qualified Roth distributions may be received tax-free when the applicable requirements are satisfied.

Can I roll over other retirement accounts into a Solo 401(k)?

A Solo 401(k) may accept eligible rollover distributions when the plan document permits them. Eligible sources may include pre-tax assets from a Traditional IRA, SEP IRA, former employer 401(k), 403(b), governmental 457(b), or another qualified retirement plan. Roth IRA assets cannot be rolled into a Solo 401(k). Designated Roth assets from another employer plan may be accepted into the plan's designated Roth account when permitted.

What happens if I hire employees after opening a Solo 401(k)?

If the business hires common-law employees who satisfy the plan's eligibility requirements, those employees generally must be included in the plan. The plan will no longer operate solely as a one-participant plan and may become subject to nondiscrimination testing, participant notices, reporting, and other standard 401(k) requirements unless an applicable exemption or safe harbor applies.

What is a SEP IRA and how does it work for small businesses?

A Simplified Employee Pension, or SEP IRA, is an employer-funded retirement arrangement for self-employed individuals and businesses. Employers make discretionary contributions to SEP-IRAs established for eligible employees, including eligible business owners. Contributions are immediately vested, and the employer may generally decide each year whether to contribute.

Who is eligible to set up a SEP IRA?

A business of any size may establish a SEP IRA, including a sole proprietorship, partnership, limited liability company, S corporation, or C corporation. SEP IRAs are commonly used by self-employed individuals and businesses with few employees, but they are not limited to owner-only businesses.

What are the SEP IRA contribution limits for 2026?

For 2026, employer contributions for an eligible employee are limited to the lesser of 25% of eligible compensation or $72,000. Special calculations apply when determining the allowable contribution for a self-employed business owner.

Are SEP IRA contributions tax-deductible for small business owners?

Employer SEP IRA contributions are generally deductible as a business expense, subject to applicable deduction limits and tax rules. Investment earnings generally grow tax-deferred until they are distributed from the account.

Can employees contribute to their own SEP IRA accounts?

Employees cannot make salary-deferral or catch-up contributions under a standard SEP plan because SEP contributions are funded by the employer. However, an employee may be able to make a regular annual Traditional IRA contribution to the same SEP-IRA when permitted by the financial institution, subject to the normal IRA contribution rules.

What are the main benefits of a SEP IRA for small businesses?

SEP IRAs offer relatively high contribution limits, flexible annual employer funding, immediate vesting, straightforward setup, and generally lower administrative requirements than many qualified retirement plans. Employers normally do not file an annual Form 5500 for a SEP plan.

How are SEP IRA contributions allocated among employees?

Under a standard SEP arrangement, an employer generally contributes the same percentage of eligible compensation for every eligible participant, including the business owner. Contributions must follow the allocation formula in the SEP plan document and applicable compensation limits.

What investment options are available in a SEP IRA?

IRA Club SBS supports traditional investment options and integration with iFlip for AI-powered investing. Permitted alternative investments may include real estate, private equity, precious metals, cryptocurrency, tax liens, and private loans. IRA Club SBS does not provide investment or structuring advice, make investment recommendations, or perform due diligence for account holders.

When is the deadline to set up and fund a SEP IRA for the previous tax year?

A SEP plan may generally be established for a tax year as late as the due date of the business's federal income tax return, including extensions. Employer contributions intended to be deducted for that year generally must also be made by the applicable tax-return due date, including extensions.

What are the withdrawal rules and penalties for SEP IRAs?

SEP IRA withdrawals are generally taxable as income. A distribution taken before age 59½ may also be subject to a 10% additional tax unless an exception applies. SEP IRA owners generally must begin required minimum distributions after reaching the applicable RMD age, which is currently age 73.

What is a Safe Harbor 401(k) and how does it work?

A Safe Harbor 401(k) is an employer-sponsored retirement plan that uses required employer contributions and other safe-harbor provisions. When the applicable requirements are satisfied, the plan is generally exempt from the annual ADP and ACP nondiscrimination tests that apply to traditional 401(k) plans.

What are the employer contribution requirements for a Safe Harbor 401(k)?

A traditional Safe Harbor 401(k) generally uses either a nonelective contribution of at least 3% of compensation for eligible employees or a qualifying matching formula. A common basic match is 100% of the first 3% an employee defers plus 50% of the next 2%. Other qualifying enhanced matching or automatic-enrollment safe-harbor formulas may also be available.

What are the 2026 Safe Harbor 401(k) contribution limits?

For 2026, employees may make combined traditional and designated Roth 401(k) elective deferrals of up to $24,500. If the plan permits catch-up contributions, participants age 50 or older may contribute an additional $8,000. Eligible participants ages 60 through 63 may use the higher $11,250 catch-up contribution instead. The combined employee and employer contribution limit is generally the lesser of 100% of compensation or $72,000, excluding eligible catch-up contributions.

How does a Safe Harbor 401(k) benefit small business owners?

A Safe Harbor 401(k) can reduce the risk of ADP and ACP testing failures, provide more predictable employer contribution requirements, and make it easier for owners and highly compensated employees to contribute without corrective refunds caused by those tests. It can also help businesses offer a competitive employee retirement benefit.

How is a Safe Harbor 401(k) different from a traditional 401(k)?

A traditional 401(k) may be subject to annual ADP and ACP nondiscrimination testing. A Safe Harbor 401(k) uses required employer contributions and satisfies additional safe-harbor rules so that it can generally avoid those tests. Traditional safe-harbor contributions are generally fully vested when made, while certain QACA safe-harbor contributions may use up to a two-year vesting schedule.

When is the deadline to start a Safe Harbor 401(k) plan for 2026?

For certain new calendar-year plans using a matching safe-harbor design, October 1, 2026 is generally the practical latest effective date because the first safe-harbor plan year must usually operate for at least three months. Different deadlines and amendment rules apply to nonelective safe-harbor designs, existing plans, QACA arrangements, and other circumstances, so employers should confirm the applicable deadline with their plan administrator.

Can I offer a Safe Harbor 401(k) with automatic enrollment or Roth options?

Yes. A Safe Harbor 401(k) may include automatic enrollment, and a qualified automatic contribution arrangement, or QACA, is a specific safe-harbor design with automatic enrollment requirements. The plan may also permit both traditional pre-tax and designated Roth 401(k) employee contributions when those options are included in the plan document.

How do AI-powered and alternative investments integrate with a Safe Harbor 401(k)?

IRA Club SBS describes integration with iFlip for AI-powered investing and may support permitted alternative investment arrangements depending on the plan's design and investment platform. Available investments are subject to the plan document, applicable fiduciary requirements, and participant eligibility. IRA Club SBS does not provide investment or structuring advice.

What are the compliance advantages of Safe Harbor 401(k) plans?

When all safe-harbor requirements are satisfied, the plan is generally exempt from annual ADP and ACP nondiscrimination testing. A Safe Harbor 401(k) is not automatically exempt from every compliance requirement. A top-heavy exemption may apply when the plan consists solely of qualifying safe-harbor contributions and meets the applicable conditions.

How much does it cost to set up and maintain a Safe Harbor 401(k)?

IRA Club SBS lists its customized Safe Harbor 401(k) service as starting at $2,950 annually, plus an active participation fee. Final pricing may depend on the plan design, number of participants, administration requirements, payroll integration, and selected services.

What is a Traditional or Roth 401(k) plan and how does it work?

A 401(k) is an employer-sponsored retirement plan that allows eligible employees to save through payroll deductions. Traditional 401(k) contributions are generally made before federal income tax, while designated Roth 401(k) contributions are made after tax. A plan may offer one or both contribution options.

How can a Traditional or Roth 401(k) help my small business and employees?

A 401(k) can help a business attract and retain employees, provide higher contribution limits than individual IRAs, and give employees a structured way to save for retirement. Employer contributions may also be deductible, subject to applicable tax rules and plan limits.

What are the annual contribution limits for a Traditional or Roth 401(k)?

For 2026, employees may make combined Traditional and designated Roth 401(k) elective deferrals of up to $24,500. If permitted by the plan, participants age 50 or older may contribute an additional $8,000. Eligible participants ages 60 through 63 may use the higher $11,250 catch-up contribution instead. Combined employee and employer contributions are generally limited to the lesser of 100% of compensation or $72,000, excluding eligible catch-up contributions.

Who is eligible to participate in a Traditional or Roth 401(k) plan?

Eligibility is defined in the plan document and must comply with federal participation rules. A plan may offer immediate eligibility or generally require employees to reach age 21 and complete up to one year of service before making elective deferrals. Additional rules may apply to eligible long-term part-time employees.

What investment choices are available in a Traditional or Roth 401(k)?

Available investments depend on the plan's design and investment platform. IRA Club SBS systems integrate with iFlip for AI-powered investing and may support permitted alternative investments such as real estate, private equity, precious metals, cryptocurrency, tax liens, and private loans. IRA Club SBS does not provide investment or structuring advice, make investment recommendations, or conduct due diligence for participants.

What are the tax benefits of a Traditional or Roth 401(k)?

Traditional 401(k) elective deferrals generally reduce current federal taxable income, and earnings grow tax-deferred until distributed. Designated Roth 401(k) contributions are made after tax, and qualified distributions of contributions and earnings may be received tax-free when applicable requirements are satisfied.

Can my business match employee contributions?

Yes. A business may make matching contributions based on employee elective deferrals or use another employer contribution formula allowed by the plan. Employer contributions may generally be deductible, subject to applicable limits, and may follow a vesting schedule unless the plan requires immediate vesting.

What happens if an employee withdraws funds early?

A taxable 401(k) distribution received before age 59½ may be subject to ordinary income tax and an additional 10% tax unless a specific exception applies. A hardship distribution may permit access to plan funds, but hardship status alone does not automatically exempt the distribution from the additional 10% tax.

What are required minimum distributions for Traditional and Roth 401(k) accounts?

Traditional 401(k) accounts are generally subject to required minimum distributions beginning at the applicable RMD age, which may be age 73 or 75 depending on the participant's date of birth. Some participants in a current employer's plan may delay RMDs until retirement if the plan permits and they are not 5% owners. Designated Roth 401(k) accounts are not subject to lifetime RMDs for the original owner.

How do I get started with a Traditional or Roth 401(k) for my business?

Schedule a consultation with IRA Club SBS to discuss workforce size, eligibility, contribution options, employer matching, investment arrangements, payroll integration, compliance requirements, and the plan structure that may be appropriate for the business.

What is a SIMPLE IRA and how does it work for small businesses?

A SIMPLE IRA is a retirement plan generally available to employers with 100 or fewer employees who earned at least $5,000 during the preceding calendar year. Eligible employees may make salary-reduction contributions, and the employer must make matching or nonelective contributions.

Who is eligible to participate in a SIMPLE IRA plan?

Generally, an employee is eligible if they received at least $5,000 in compensation from the employer during any two preceding calendar years and are reasonably expected to receive at least $5,000 during the current year. Employers may use less restrictive eligibility requirements.

What are the contribution limits for SIMPLE IRAs in 2026?

For 2026, the standard employee salary-reduction contribution limit is $17,000. A higher $18,100 limit applies to certain applicable SIMPLE plans. The general catch-up contribution for eligible participants age 50 or older is $4,000, while a $3,850 catch-up applies to certain plans using the higher contribution limit. Eligible participants ages 60 through 63 may use the higher $5,250 catch-up contribution instead.

How does employer matching work in a SIMPLE IRA?

Employers generally choose between matching employee salary-reduction contributions dollar-for-dollar up to 3% of compensation or making a 2% nonelective contribution for each eligible employee. Certain employers with 26 to 100 employees must provide enhanced employer contributions to use the higher employee contribution limit.

What are the main benefits of a SIMPLE IRA for small business owners?

A SIMPLE IRA is generally less complex and less expensive to establish and administer than many qualified retirement plans. It does not normally require an annual employer IRS return, employer contributions may be deductible, and it provides employees with a structured retirement savings benefit.

How do employees make contributions to a SIMPLE IRA?

Employees elect to contribute a specified dollar amount or percentage of compensation through automatic payroll deductions. These salary-reduction contributions are generally made on a pre-tax basis for federal income-tax purposes and deposited into each employee's SIMPLE IRA.

What investment options are available in a SIMPLE IRA?

IRA Club SBS systems integrate with iFlip for AI-powered investing and support permitted alternative investments such as real estate, private equity, precious metals, cryptocurrency, tax liens, and private loans. IRA Club SBS does not provide investment or structuring advice, make investment recommendations, or conduct due diligence for account holders.

Are SIMPLE IRA contributions tax-deductible?

Employee salary-reduction contributions generally reduce federal taxable income for the year in which they are made. Employer matching and nonelective contributions are also generally deductible as business expenses, subject to applicable tax rules.

What are the rules for withdrawing money from a SIMPLE IRA?

SIMPLE IRA withdrawals are generally taxable. A taxable withdrawal before age 59½ may also be subject to a 10% additional tax unless an exception applies. The additional tax generally increases to 25% when the withdrawal occurs within the first two years of participation.

How do I set up a SIMPLE IRA plan for my small business?

An employer can establish a SIMPLE IRA using IRS Form 5304-SIMPLE, Form 5305-SIMPLE, or an approved financial institution's prototype plan document. The employer must provide required information to eligible employees and establish a SIMPLE IRA account for each eligible participant.

What is a payroll deduction IRA, and how does it work?

A payroll deduction IRA allows employees to contribute automatically to an individual Traditional or Roth IRA through after-tax paycheck deductions. The employee opens the IRA, authorizes a deduction amount, and the employer forwards the authorized contribution to the employee's IRA each pay period.

Solo 401(k) Contribution Limits 2026 Under the Internal Revenue Code

March 20, 2026
Est. Read Time: 4 minutes

Strategic Advice for Business Owners to Optimize Retirement Plans

Quick Summary / Key Takeaways

A Solo 401(k) permits contributions in two capacities: employee elective deferrals under Internal Revenue Code §402(g) and employer profit-sharing contributions, subject to the annual additions limit under Internal Revenue Code §415(c).
For 2026, the elective deferral limit under §402(g) is $24,500. The defined contribution annual additions limit under Internal Revenue Code §415(c)(1)(A) is $72,000, excluding catch-up contributions. Eligible participants age 50 or older may contribute an additional $8,000 to $11,250, dependent on their age, under Internal Revenue Code §414(v)(2)(B)(i).
Total allowable contributions depend on earned income and statutory calculation rules. For self-employed individuals, contributions are based on net earnings from self-employment as defined under the Internal Revenue Code and applicable IRS guidance.
Exceeding contribution limits may require corrective action under IRS procedures to maintain plan qualification.
Plan administration, recordkeeping, and required filings must align with applicable Internal Revenue Code requirements and, if applicable, ERISA reporting standards.

To find the best plan cost for your business, fill out the discovery form.

Saving for retirement while operating a business requires coordination between income, tax reporting, and statutory contribution limits. A Solo 401(k) is a qualified retirement plan under Internal Revenue Code §401(k) designed for a business owner with no eligible common-law employees, other than a spouse if applicable.
A Solo 401(k) permits contributions in two capacities: as an employee through elective deferrals under Internal Revenue Code §402(g), and as an employer through profit-sharing contributions subject to the annual additions limit under Internal Revenue Code §415(c). Understanding the Solo 401(k) contribution limits for 2026 requires reviewing the applicable statutory limits and calculation rules.
For 2026, the elective deferral limit under Internal Revenue Code §402(g) is $24,500. The defined contribution annual additions limit under Internal Revenue Code §415(c)(1)(A) is $72,000, excluding catch-up contributions. Eligible participants age 50 or older may contribute an additional $8,000 under Internal Revenue Code §414(v)(2)(B)(i). Total allowable contributions depend on earned income and the calculation methods defined under the Internal Revenue Code.
Contribution limits for IRAs established under Internal Revenue Code §408 differ from those applicable to qualified plans. For 2026, the IRA contribution limit is $7,500, with an additional $1,100 catch-up contribution permitted for individuals age 50 or older.
This guide explains how statutory contribution limits operate, how business structure may affect calculation methods, and what compliance considerations apply under federal law.

2026 Solo 401(k) Contribution Breakdown Under the Internal Revenue Code

Contribution Category	2026 Statutory Limit	Participant Capacity	Applicable Code Reference
Employee Deferral	$24,500	Owner/Employee	Internal Revenue Code §402(g)
Employer Profit-Sharing Contribution	Subject to compensation-based calculation; total contributions limited under Internal Revenue Code §415(c)	Employer	Internal Revenue Code §415(c)
Catch-Up Contribution (Age 50+)	$8,000	Eligible Participant Age 50 or Older	Internal Revenue Code §414(v)(2)(B)(i)
Annual Additions Limit (Excludes Catch-Up)	$72,000	Combined Employee and Employer Contributions	Internal Revenue Code §415(c)(1)(A)

Comparison of Solo 401(k) and Alternative Retirement Plans (2026 Limits)

Plan Feature	Solo 401(k)	SEP IRA	SIMPLE IRA
Maximum Contribution – 2026	Up to $72,000 under Internal Revenue Code §415(c), plus $8,000 catch-up if eligible	Up to $72,000 under Internal Revenue Code §415(c)	Elective deferral limit of $16,500; catch-up contributions permitted under applicable IRS rules
Catch-Up Contributions (Age 50+)	$8,000 under Internal Revenue Code §414(v)(2)(B)(i)	Not applicable	Permitted under SIMPLE IRA catch-up provisions (subject to applicable IRS limits)
Roth Contribution Option	Permitted if the plan document allows designated Roth contributions under Internal Revenue Code §402A	Not permitted	Roth SIMPLE IRA contributions permitted, subject to plan provisions and Internal Revenue Code rules
Participant Loan Feature	Permitted if allowed under plan terms and subject to Internal Revenue Code §72(p) limits	Not permitted	Not Permitted

Solo 401(k) Eligibility and Initial Plan Setup Checklist

Verify the business has no eligible common-law employees other than the owner and, if applicable, the owner’s spouse, consistent with owner-only plan requirements under the Internal Revenue Code and applicable Department of Labor guidance.
Obtain an Employer Identification Number (EIN) for the retirement plan, if required for plan administration, banking, and reporting purposes.
Review service provider agreements, fee disclosures, and the scope of administrative and recordkeeping responsibilities under the selected plan structure.
Establish a plan account with the designated financial institution to hold plan assets in accordance with the written plan document and applicable federal requirements.

Ongoing Contribution and Compliance Review Checklist

Calculate net earnings from self-employment in accordance with Internal Revenue Code definitions to determine the contribution base.
Apply the applicable 2026 statutory limits under Internal Revenue Code §402(g) (elective deferrals), §414(v) (catch-up contributions), and §415(c) (annual additions) when determining contribution amounts.
Maintain records of elective deferrals and employer contributions consistent with the plan document, payroll records, and federal reporting requirements.
Review IRS publications and applicable federal guidance periodically for updates to statutory contribution limits, reporting thresholds, and qualification requirements.

Frequently Asked Questions

Section 1: BASICS OF SOLO 401K LIMITS

FAQ 1: What are the total Solo 401(k) contribution limits for 2026 under the Internal Revenue Code?

For 2026, the elective deferral limit under Internal Revenue Code §402(g) is $24,500. Eligible participants age 50 or older may contribute an additional $8,000 to $11,250 catch-up contribution, dependent on their age, under Internal Revenue Code §414(v)(2)(B)(i).

The defined contribution annual additions limit under Internal Revenue Code §415(c)(1)(A) is $72,000, excluding catch-up contributions. This annual additions limit applies to the combined total of employee elective deferrals and employer profit-sharing contributions.

Accordingly, for 2026, total contributions to a Solo 401(k) may reach $72,000, or $79,000 (up to $83,250 for ages 60 – 63) for an eligible participant age 50 – 59; 64+, subject to compensation-based calculation rules and statutory limits under the Internal Revenue Code.

Designated Roth contributions may be permitted if the written plan document allows Roth deferrals under Internal Revenue Code §402A. Contribution allocations must remain within applicable statutory limits.

Takeaway: For 2026, Solo 401(k) contribution limits are determined by Internal Revenue Code §402(g), §414(v), and §415(c). Total allowable contributions depend on earned income and statutory calculation rules under federal law.

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FAQ 2: How do employee elective deferrals operate within Solo 401(k) contribution limits for 2026?

For 2026, an individual may defer up to $24,500 of eligible compensation as an employee under Internal Revenue Code §402(g). Elective deferrals are one component of total contributions permitted under a Solo 401(k) and are subject to statutory limits.

Participants age 50 or older may contribute an additional $8,000 to $11,250 catch-up contribution, dependent on their age, under Internal Revenue Code §414(v)(2)(B)(i). Catch-up contributions are permitted in addition to the annual additions limit under Internal Revenue Code §415(c)(1)(A).

Elective deferrals may be made on a pre-tax basis or, if permitted by the written plan document, as designated Roth contributions under Internal Revenue Code §402A. The tax treatment of contributions depends on plan provisions and applicable federal law.

Takeaway: Employee elective deferrals under Internal Revenue Code §402(g) represent one portion of total Solo 401(k) contributions. Applicable limits, including catch-up provisions, are determined by federal statute and participant eligibility.

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FAQ 3: What is the maximum employer profit-sharing contribution under a Solo 401(k)?

Employer profit-sharing contributions to a Solo 401(k) are subject to statutory limits under Internal Revenue Code §415(c). For an incorporated business, the maximum employer contribution is generally limited to 25% of eligible compensation, as defined under the Internal Revenue Code and the written plan document.

For a self-employed individual, the contribution calculation is based on net earnings from self-employment, as defined under the Internal Revenue Code. Due to the adjustment for self-employment tax and contribution calculations, the effective contribution rate is generally up to 20% of adjusted net earnings.

Employer contributions, when combined with employee elective deferrals, may not exceed the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions under §414(v).

Employer profit-sharing contributions are typically made on a pre-tax basis in accordance with the plan document and applicable federal law.

Takeaway: Employer profit-sharing contributions are determined by compensation-based formulas and are subject to the annual additions limit under Internal Revenue Code §415(c). Total permissible contributions depend on earned income and statutory calculation rules under federal law.

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Section 2: CALCULATION AND INCOME

FAQ 4: How does business structure affect Solo 401(k) contribution calculations?

Business structure affects how compensation is defined for purposes of employer profit-sharing contributions under Internal Revenue Code §415(c).

For an S corporation or C corporation, employer contributions are generally limited to 25% of W-2 wages paid to the participant, as defined under the Internal Revenue Code and the written plan document.

For a sole proprietor or single-member LLC taxed as a disregarded entity, employer contributions are based on net earnings from self-employment, as defined under the Internal Revenue Code. Due to the required adjustment for one-half of self-employment tax and contribution calculations, the effective contribution rate is generally up to 20% of adjusted net earnings.

All employer contributions, when combined with employee elective deferrals under Internal Revenue Code §402(g), remain subject to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions under §414(v).

Takeaway: Business structure determines how compensation is calculated for employer contribution purposes under Internal Revenue Code §415(c). Total permissible contributions depend on earned income and statutory calculation rules.

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FAQ 5: Is a minimum income required to reach the maximum Solo 401(k) contribution limits for 2026?

The maximum Solo 401(k) contribution for 2026 is determined by statutory limits under Internal Revenue Code §402(g) and §415(c), as well as the participant’s eligible compensation. For 2026, the annual additions limit under §415(c)(1)(A) is $72,000, excluding catch-up contributions under §414(v).

To reach the maximum permitted contribution, the business must generate sufficient earned income to support both employee elective deferrals and employer profit-sharing contributions under the compensation-based calculation rules defined by the Internal Revenue Code.

For an S corporation, employer contributions are calculated as a percentage of W-2 wages. For a sole proprietor or single-member LLC taxed as a disregarded entity, employer contributions are based on adjusted net earnings from self-employment, as defined under federal law. The income required to reach the statutory limit varies depending on the compensation structure and calculation method.

Contributions may be made in amounts below the statutory maximum, provided they do not exceed eligible compensation or applicable federal limits.

Takeaway: The ability to reach the maximum Solo 401(k) contribution depends on earned income and statutory calculation rules under Internal Revenue Code §402(g) and §415(c). Contribution amounts are limited by compensation and federal law.

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FAQ 6: Can a Solo 401(k) be established for side business income?

A Solo 401(k) may be established for a business that generates self-employment income, provided the business has no eligible common-law employees other than the owner and, if applicable, the owner’s spouse. Eligibility is determined under applicable Department of Labor regulations and Internal Revenue Code definitions.

Contributions to the Solo 401(k) are limited to the earned income produced by that business, as defined under the Internal Revenue Code.

The elective deferral limit under Internal Revenue Code §402(g) is $24,500 for 2026. This limit applies on a per-person basis across all 401(k) plans in which an individual participates. Elective deferrals made to an employer-sponsored 401(k) plan through separate employment reduce the remaining amount available for deferral to a Solo 401(k).

Employer profit-sharing contributions from the side business are calculated separately, based on compensation from that business, and remain subject to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions under §414(v).

Takeaway: A Solo 401(k) may be used for side business income if owner-only eligibility requirements are satisfied. Elective deferral limits apply per individual across all 401(k) plans, and total contributions remain subject to statutory limits under federal law.

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Section 3: AGE AND CATCH-UP RULES

FAQ 7: What are the catch-up contribution rules for individuals age 50 or older under a Solo 401(k) in 2026?

For 2026, individuals age 50 or older may contribute an additional $8,000 (ages 50 – 59; 64+) to $11,250 (ages 60 – 63) catch-up, dependent on their age under Internal Revenue Code §414(v)(2)(B)(i). The participant must reach age 50 by the end of the calendar year to be eligible.

The catch-up amount is permitted in addition to the elective deferral limit under Internal Revenue Code §402(g), which is $24,500 for 2026. Accordingly, an eligible participant may defer up to $32,500 in total elective deferrals for 2026, subject to compensation and plan terms. Those ages 60 – 63 get a boost of $35,750 in total elective deferrals for 2026.

Catch-up contributions are permitted in addition to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026. Catch-up amounts may be made on a pre-tax basis or, if permitted by the written plan document, as designated Roth contributions under Internal Revenue Code §402A.

Takeaway: For 2026, eligible participants age 50 or older may make an additional $8,000 to $11,250 catch-up contribution, dependent on their age, under Internal Revenue Code §414(v). Catch-up contributions apply in addition to elective deferral and annual additions limits, subject to statutory requirements and plan provisions.

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FAQ 8: How does the SECURE 2.0 Act affect Solo 401(k) contribution rules for 2026?

The SECURE 2.0 Act amended certain provisions applicable to qualified retirement plans, including catch-up contribution treatment and Roth contribution options.

For 2026, individuals age 50 or older may make a catch-up contribution of $8,000 under Internal Revenue Code §414(v)(2)(B)(i). A special “super” catch-up of $11,250 is available for ages 60–63. Catch-up contributions are permitted in addition to the elective deferral limit under Internal Revenue Code §402(g), which is $24,500 for 2026.

SECURE 2.0 also permits employer contributions to be designated as Roth contributions in certain qualified plans, if allowed under the written plan document and adopted by the plan sponsor. Availability depends on plan design and administrative implementation.

The Act includes provisions requiring certain higher-income participants to make catch-up contributions on a Roth basis if earned more than $150,000 from a business.

Total contributions remain subject to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions.

Takeaway: SECURE 2.0 modified certain operational rules affecting catch-up contributions and Roth treatment within qualified plans. Contribution limits for 2026 remain defined by Internal Revenue Code §402(g), §414(v), and §415(c), as adjusted by IRS guidance.

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FAQ 9: Are there special catch-up contribution limits for participants age 60 to 63 under a Solo 401(k) in 2026?

Under SECURE 2.0 provisions applicable in 2026, participants who attain age 60, 61, 62, or 63 during the calendar year may be eligible for an increased catch-up contribution under Internal Revenue Code §414(v), if permitted by the written plan document.

For 2026, the standard catch-up contribution for individuals age 50 or older is $8,000. For eligible participants aged 60 to 63, the catch-up limit is increased to $11,250.

Catch-up contributions are permitted in addition to the elective deferral limit under Internal Revenue Code §402(g), which is $24,500 for 2026. Catch-up amounts are also permitted in addition to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026.

Availability and administration of the higher catch-up amount depend on plan terms and federal regulatory guidance.

Takeaway: For 2026, participants aged 60 to 63 may qualify for an increased catch-up contribution equal to 150% of the standard age-50 catch-up amount. Eligibility and administration are governed by Internal Revenue Code §414(v) and applicable IRS guidance.

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Section 4: TAX AND COMPLIANCE

FAQ 10: Can Roth contributions be made under Solo 401(k) limits for 2026?

A Solo 401(k) may permit designated Roth contributions for the employee elective deferral portion, if the written plan document allows. For 2026, the elective deferral limit under Internal Revenue Code §402(g) is $24,500. This limit applies in total, whether contributions are made on a pre-tax or Roth basis.

Under SECURE 2.0 provisions, certain plans may also permit employer contributions to be designated as Roth contributions if adopted under the written plan document and administered in accordance with federal requirements. Availability depends on plan design and implementation.

Roth contributions are made with after-tax compensation. Pre-tax contributions are generally deductible to the employer, subject to Internal Revenue Code provisions. The tax treatment of distributions is governed by applicable statutory rules.

The qualified plan custodian is responsible for holding plan assets, maintaining records, titling assets, and issuing required IRS reporting forms, including Form 1099-R and Form 5498, where applicable, or works with a self-directed administrator that handles these responsibilities.

Takeaway: A Solo 401(k) may permit Roth employee deferrals and, in certain cases, Roth employer contributions if authorized under the written plan document. Contribution limits for 2026 are governed by Internal Revenue Code §402(g) and related statutory provisions.

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FAQ 11: What happens if Solo 401(k) contribution limits are exceeded?

If total contributions exceed applicable limits under Internal Revenue Code §402(g) or §415(c), the excess amount must generally be corrected in accordance with Internal Revenue Code provisions and IRS procedures. Correction may require removal of the excess contribution and any allocable earnings within applicable deadlines.

If an excess contribution is not corrected within the required timeframes, additional taxes or penalties may apply under federal law. Certain excess amounts may be subject to excise taxes under Internal Revenue Code provisions governing excess contributions. Reporting obligations apply to both the participant and the plan.

Takeaway: Exceeding Solo 401(k) contribution limits may require corrective action under Internal Revenue Code §402(g) and §415(c). Correction procedures and reporting requirements are governed by federal tax rules and IRS guidance.

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FAQ 12: How are Solo 401(k) contributions reported for federal tax purposes?

Reporting of Solo 401(k) contributions depends on business structure and contribution type. Employee elective deferrals and employer profit-sharing contributions are treated differently under federal tax rules.

For an S corporation, employee elective deferrals are generally reflected on Form W-2. Employer contributions are typically deducted on the business tax return, subject to Internal Revenue Code provisions governing deductible plan contributions.

For a sole proprietor, contributions are generally reported on Schedule 1 of Form 1040 and related schedules, in accordance with Internal Revenue Code requirements. The deductible amount depends on net earnings from self-employment and applicable statutory limits.

Takeaway: Solo 401(k) contributions are reported based on business structure and contribution type under federal tax rules. Reporting requirements are governed by the Internal Revenue Code and IRS guidance.

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Section 5: STRATEGIC PLANNING

FAQ 13: Can a Solo 401(k) be combined with other retirement plans?

An individual may participate in a Solo 401(k) and also contribute to a Traditional IRA or Roth IRA, though the ability to deduct IRA contributions may be limited by their income.

For 2026, the elective deferral limit under Internal Revenue Code §402(g) is $24,500. This limit applies on a per-person basis across all 401(k) plans in which an individual participates. If elective deferrals are made to another employer-sponsored 401(k), the remaining available deferral amount for the Solo 401(k) is reduced accordingly.

Employer profit-sharing contributions under a Solo 401(k) are calculated separately based on compensation from the self-employment activity. Total contributions remain subject to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions under §414(v).

IRA contribution limits are separate from 401(k) limits. For 2026, the IRA contribution limit is $7,500, with an additional $1,100 catch-up contribution permitted for individuals age 50 or older, subject to eligibility requirements. Although a contribution can be made to an IRA, the benefit of IRA contribution deductions might be limited.

Takeaway: Participation in a Solo 401(k) does not prohibit contributions to other retirement arrangements. Elective deferral limits apply per individual across all 401(k) plans, while IRA limits are separate and governed by Internal Revenue Code provisions and applicable income thresholds.

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FAQ 14: How do Solo 401(k) limits compare to SEP IRA limits for 2026?

A Solo 401(k) and a SEP IRA are both employer-sponsored retirement arrangements, but their contribution structures differ under the Internal Revenue Code.

Under a Solo 401(k), contributions may include employee elective deferrals and employer profit-sharing contributions. For 2026, the elective deferral limit under Internal Revenue Code §402(g) is $24,500. Total contributions are subject to the annual additions limit under Internal Revenue Code §415(c)(1)(A), which is $72,000 for 2026, excluding catch-up contributions under §414(v).

A SEP IRA permits employer contributions only. SEP contributions are generally limited to the lesser of 25% of an employee’s total compensation up to $72,000 for 2026. A SEP IRA does not permit employee elective deferrals.

Because a Solo 401(k) includes an elective deferral component in addition to employer contributions, the contribution calculation differs from a SEP IRA at the same income level. Actual contribution amounts depend on compensation, business structure, and applicable statutory limits.

Takeaway: Both Solo 401(k) plans and SEP IRAs are subject to the annual additions limit under Internal Revenue Code §415(c). A Solo 401(k) permits elective deferrals in addition to employer contributions, while a SEP IRA permits employer contributions only. Contribution amounts are determined by earned income and statutory calculation rules.

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FAQ 15: What is the deadline for making contributions to a Solo 401(k)?

Solo 401(k) contributions are generally due by your business’s tax filing deadline (including extensions) for the tax year, which is typically April 15 for sole proprietors/single-member LLCs, or March 15 for S-Corps and Partnerships. If the business files for an extension, the new deadline is generally October 15 for sole proprietors or single-member LLCs.

Employee elective deferrals must generally be elected by the end of the plan year. Employer profit-sharing contributions may generally be made up to the business’s tax filing deadline, including extensions, subject to plan terms and federal requirements.

A Solo 401(k) plan must generally be adopted by December 31 of the tax year in question to make employee deferral contributions for that same year.

Takeaway: Solo 401(k) contribution deadlines vary based on contribution type and tax filing deadlines. Establishment and funding requirements are defined by the Internal Revenue Code and IRS guidance.

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Article Summary

Maximize your savings with the 2026 solo 401k contribution limits. Learn how to contribute as both employee and employer to reach your retirement goals faster.

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