Solo 401(k) Plans in 2026: Contribution Limits, Tax Benefits, and When They May Be a Strong Option for Small Business Owners
- kendallmaccagnan
- 1 day ago
- 9 min read
Learn how Solo 401(k) plans work in 2026, including contribution limits, tax benefits, eligibility rules, and key deadlines for small business owners.
By Kendall Maccagnan, CPA, CFP® and Financial Advisor in Tampa, Florida
Key Takeaways
A Solo 401(k) is designed for self-employed individuals and business owners with no employees (other than a spouse), and may allow for higher contribution flexibility compared to other retirement plans
In 2026, total contributions may reach up to $72,000 or more depending on eligibility, with additional catch up contributions available for those age 50 and older
The dual contribution structure allows business owners to contribute to a traditional Solo 401(k) as both an employee and employer, which may provide tax advantages depending on eligibility, income and contribution elections
Recent updates under the SECURE 2.0 Act have introduced new rules that may affect how Solo 401(k) plans operate in 2026
Introduction
Self-employed individuals and small business owners are often responsible for funding their own retirement. As a result, selecting the right retirement vehicle can play an important role in long term financial planning. One option to be considered is the Solo 401(k). A Solo 401(k), also known as an individual 401(k) or one participant 401(k), is a retirement plan designed for self-employed individuals or business owners with no employees (other than a spouse). In 2026, it may allow for higher contribution limits through a combination of employee deferrals and employer contributions, along with potential tax advantages depending on how contributions are structured.
Is a Solo 401(k) the Right Retirement Plan for Your Business in 2026?
What is a Solo 401(k)?
A Solo 401(k) is a traditional 401(k) plan covering a business owner with no employees (with an employee spouse being the exception to the rule) and follows the same rules and requirements as any other 401(k) plan. Business owners have several options when choosing a retirement plan including SEP IRA plans, SIMPLE IRA plans, and defined benefit plans. What distinguishes a Solo 401(k) from SEP IRA and SIMPLE IRA plans is its dual contribution structure, which allows a business owner to contribute both as an employee and as an employer, often resulting in higher total contribution potential depending on income.
Who qualifies for a Solo 401(k):
The Solo 401(k) is available to self-employed individuals and business owners across a variety of business structures including sole proprietors, single member LLCs, and S-corporations provided the business has no common law employees other than the owner and their spouse. This audience may include freelancers, independent contractors, consultants, and any self-employed individual with net earnings from self-employment.
A spouse who earns income from the business may also participate in the plan, which can increase total household contribution limits and may provide additional tax advantages depending on the household’s income and tax situation.
The employee restriction:
If you hire employees and they meet the plan eligibility requirements, you must include them in the plan and their elective deferrals will be subject to nondiscrimination testing, unless the plan is a safe harbor plan or other plan exempt from testing per the IRS guidance. In practical terms hiring full time employee who meets your plan's eligibility requirements would generally disqualify the business from maintaining a Solo 401(k). Business owners who anticipate hiring employees in the near future should consider factoring this into their plan selection decision.
How Does a Solo 401(k) Work for Self-Employed Individuals?
A Solo 401(k) operates similarly to a traditional employer sponsored 401(k) plan with the key distinction being a self-employed individual or business owner functions as both the employee and employer. This is what makes the Solo 401(k) a unique planning tool because it allows for higher annual contribution limits compared to some other retirement plans.
The employee contribution: As the employee, you can make elective deferrals into the plan or, if available, into the Roth basis. Employee deferral limits for 2026 have been included below. In any given year an individual can defer up to the deferral limit or 100% of compensation, whichever is less. This portion of the contribution reduces taxable income in the year it is made if contributed on a pre-tax basis.
The employer contribution: As the employer, you can also make a profit sharing contribution on top of your employee deferral. For incorporated businesses such as S-corporations, this is generally up to 25% of W-2 wages. For sole proprietors and single member LLCs, the calculation is based on net self-employment income and effectively amounts to approximately 20% of net earnings after accounting for the deduction for self-employment tax. The employer contribution is discretionary which means you are not required to make it every year providing flexibility in years when income is lower or unpredictable.
2026 Contribution Limits by Age
One notable feature of the Solo 401(k) is its contribution capacity. Because you contribute as both employee and employer, total annual contributions for eligible participants in 2026 can reach up to $72,000 with higher limits available for those eligible for catch up contributions. This may be higher than what some self-employed individuals can contribute through other retirement plans at similar income levels.
Age of Contributor | 2026 Employee Limit | Total Max Contribution Limit (Employee + Employer) |
Under age 50 | $24,500 | $72,000 |
Age 50+ and age 64+ | $32,500 | $80,000 |
Ages 60-63 (Secure Act 2.0) | $35,750 | $83,250 |
A few important notes on the table above:
The employee deferral limit applies across all 401(k) plans you participate in (see note below)
The employer profit sharing contribution is generally limited to 25% of total compensation up to $360,000 in 2026. Note that for sole proprietors and single-member LLCs taxed as sole proprietors, the effective rate is approximately 20% of net self-employment income due to the way the IRS calculates the deduction
Catch up contributions for ages 60-63 are available under SECURE 2.0 and remain at $11,250 for 2026
Beginning in 2026, the SECURE 2.0 Act is expected to require participants age 50+ who earned more than $150,000 in prior year FICA wages to make catch up contributions on a Roth basis rather than pre-tax basis
Note on employee deferral limit:
The employee deferral limit of $24,500 applies across all 401(k) plans you participate in meaning if you also contribute to a 401(k) through a separate employer, your combined employee deferrals across all plans cannot exceed $24,500 for 2026. However, the $72,000 total contribution limit applies per unrelated employer. This means if you have a day job where you and your employer contribute a combined $30,000 to your workplace 401(k), you may still be able to contribute up to a full $72,000 through your Solo 401(k) using profit sharing contributions for your side business, provided you have sufficient self-employment income to support it. Because the calculation depends on your specific income level and business structure, it may be helpful to discuss your situation with a qualified tax advisor.
Tax Benefits
A business owner who maximizes both employee and employer contributions to a traditional pre-tax Solo 401(k) may reduce their taxable income up to applicable contribution limits in a given year which can make it a useful planning tool for self-employed individuals depending on the individual's circumstances. Like other qualified retirement accounts, all investment earnings inside the plan grow tax deferred. Most Solo 401(k) plans also offer a Roth contribution option, allowing after tax contributions to grow tax free and generally be withdrawn tax free in retirement, provided IRS requirements are met. Unlike a Roth IRA, the Solo 401(k) generally has no income based contribution limits making the Roth option accessible to high income business owners who may be ineligible to contribute directly to a Roth IRA.
Key Rules and Deadlines
Plan establishment: For most business structures the Solo 401(k) must be established by December 31 of the tax year for which you want to make contributions. Under SECURE 2.0 sole proprietors and single member LLCs taxed as sole proprietors with no employees have an extended window and the plan can be established as late as the tax filing deadline without extensions, generally April 15 of the following year.
Employee deferral election: For existing plans the election to defer must be made by December 31 of the contribution year. Under SECURE 2.0 sole proprietors and single member LLCs establishing a new plan have a first year grace period to make their initial election as late as their tax filing deadline which is typically April 15 of the following year for calendar year filers. Regardless of when the election is made the actual funding of employee deferrals can generally be deposited up until the tax filing deadline including extensions, but timing may vary depending on business structure.
Employer profit-sharing contributions: These can be made any time up to the business tax filing deadline including extensions which gives business owners flexibility to assess income before deciding how much to contribute.
Form 5500-EZ: Once Solo 401(k) plan assets exceed $250,000 at year end an annual filing of Form 5500-EZ is required by July 31 of the following year.
Required Minimum Distributions: RMDs must begin at age 73.
SECURE 2.0 Changes Affecting Solo 401(k) Owners in 2026
The SECURE 2.0 Act introduced several meaningful updates to Solo 401(k) plans that business owners should be aware of heading into 2026.
Super catch-up contributions for ages 60-63: Participants who turn age 60, 61, 62, or 63 during the plan year may make an enhanced catch-up contribution of $11,250 in 2026 rather than the standard $8,000.
Mandatory Roth catch-up for high earners: Beginning in 2026 participants age 50 or older who earned more than $150,000 (indexed for inflation) in prior year FICA wages must make catch up contributions on a Roth after tax basis rather than pre tax. How this rule applies will depend on your specific business structure and compensation arrangements business owners may want to confirm their obligations with a qualified tax advisor.
Roth employer contributions: As covered in the Tax Benefits section SECURE 2.0 now permits employer profit sharing contributions to be designated as Roth if the plan document allows it.
Extended establishment deadline: Sole proprietors and single member LLCs taxed as sole proprietors with no employees may now establish a Solo 401(k) after December 31 and still make employer contributions for the prior year provided the plan is adopted by the tax filing deadline without extensions.
Plan amendment deadline: Most Solo 401(k) plans must formally adopt SECURE 2.0 amendments by December 31 2026. Business owners should contact their plan provider to confirm this has been addressed to avoid potential plan disqualification.
Is a Solo 401(k) Right for You?
A Solo 401(k) may be worth exploring if one or more of the following apply to your situation:
You are self-employed or own a business with no full time employees other than yourself or a spouse
You want to maximize annual retirement contributions and tax deductions beyond what a SEP IRA or SIMPLE IRA would allow at your income level
You have high or variable income and want flexibility in how much you contribute year to year
You are interested in Roth contribution options that are not subject to income based limits
You have a day job with a 401(k) and a side business and want to maximize employer profit sharing contributions through a Solo 401(k) for your self-employment income
You are between ages 60 and 63 and want to take advantage of the enhanced super catch up contribution available under SECURE 2.0
Solo 401(k) Contribution Limits 2026 (Quick Chart) | |
Who qualifies | Self-employed individuals and business owners with no full time employees other than owner and spouse |
Business structures | Sole proprietors, single member LLCs, S corporations |
2026 employee deferral limit | $24,500 (under age 50); $32,500 (age 50+); $35,750 (ages 60-63) |
2026 total contribution limit | $72,000 (under age 50); $80,000 (age 50+); $83,250 (ages 60-63) |
Employer contribution limit | Up to 25% of W-2 wages (S-corps); ~20% of net self-employment income (sole proprietors) |
Compensation limit | $360,000 for 2026 |
Roth option available | Yes; employee deferrals and employer contributions if plan document allows |
Nondiscrimination testing | Not required as long as there are no eligible non owner employees |
Plan establishment deadline | December 31 generally; April 15 for sole proprietors under SECURE 2.0 |
Employer contribution deadline | Tax filing deadline including extensions |
Form 5500-EZ required | Yes once plan assets exceed $250,000; due July 31 annually |
RMDs begin | Age 73 |
Every business owner's situation is different. The right retirement plan depends on your business structure, income level, tax situation, and long term financial goals. A qualified financial advisor or CPA can help you evaluate whether a Solo 401(k) is the right fit for your specific circumstances.
This content is provided for educational and informational purposes only and should not be construed as investment, tax, or legal advice. It is not intended as a solicitation or offer to provide advisory services in any jurisdiction where Off The Bay Wealth, LLC is not properly registered or otherwise permitted to operate. Information presented is based on sources believed to be reliable; however, accuracy and completeness are not guaranteed. This material is not intended to be a comprehensive analysis of all topics discussed. IRS provisions are subject to ongoing guidance and regulatory updates. Any financial decisions should be made in consideration of your individual circumstances, including your goals, risk tolerance, and time horizon. Investing involves risk, including the potential loss of principal.
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