--- title: "Solo 401(k) Profile" description: "Sourced Solo 401(k) profile: 2026 employee deferral $24,500; employer profit-sharing up to 25% of net self-employment income; §415 limit $72,000." canonical: https://www.getswoopr.com/accounts/solo-401k/ source: "Swoopr Investment: https://www.getswoopr.com" --- ## Direct Answer A Solo 401(k) (individual 401(k) or one-participant 401(k)) is a full 401(k) plan for self-employed individuals with no employees other than a spouse. The 2026 total annual limit is $72,000: up to $24,500 in employee elective deferrals (plus age 50+ catch-up of $8,000 or ages 60-63 catch-up of $11,250), plus employer profit-sharing up to 25% of net self-employment income. Solo 401(k) allows Roth contributions and may permit after-tax contributions for a "mega backdoor Roth." # Solo 401(k) Profile: 2026 Contribution Limits for Self-Employed This profile cites IRS primary sources. It does not provide personalized tax or financial advice. Solo 401(k) plan document requirements and deadlines vary by provider; verify with your plan document and tax advisor. ## 2026 Contribution Limits | Component | 2026 Limit | | --- | --- | | Employee elective deferral (pre-tax + Roth) | $24,500 | | Age 50+ catch-up (standard) | $8,000 additional | | Ages 60-63 higher catch-up (SECURE 2.0) | $11,250 additional | | Employer profit-sharing contribution | Up to 25% of net SE income (after SE tax deduction) | | Total annual additions (§415) | $72,000 (+ catch-up for age 50+) | For the self-employed, the effective employer profit-sharing rate is approximately 20% of gross net SE profit (after deducting the self-employment tax deduction). A person with $100,000 net SE profit can contribute roughly $18,587 as employer contribution plus up to $24,500 employee deferral = $43,087 total. Source: IRS Notice 2025-67; IRS Publication 560. ## Eligibility and Plan Setup A Solo 401(k) is available to self-employed individuals and business owners (sole proprietors, LLC members, S-corp owners who pay themselves W-2 wages, partners) with no employees other than a spouse. The spouse of the business owner may participate if they are employed by the business. **Plan establishment deadline:** Generally a Solo 401(k) must be adopted by December 31 of the tax year for which contributions are made. Since 2023, a sole proprietor with no employees can adopt a 401(k) after year end, up to the tax filing deadline (without extensions), per IRS Publication 560. SEP IRAs can be established as late as the filing deadline including extensions. **Loss of eligibility:** If a non-spouse employee works more than 1,000 hours in any plan year, the plan must be converted to a standard 401(k) plan with ERISA compliance requirements (nondiscrimination testing, Form 5500, etc.). **Form 5500:** Required when plan assets exceed $250,000 at year-end (Form 5500-EZ for one-participant plans). ## Roth and Mega Backdoor Roth Solo 401(k) plans can offer both traditional (pre-tax) and Roth designations for employee elective deferrals, subject to the $24,500 combined limit. There are no income limits for Roth 401(k) contributions. Some Solo 401(k) plan documents also allow after-tax (non-Roth) contributions and in-plan Roth conversions, enabling a "mega backdoor Roth" strategy. Under this strategy, the self-employed person contributes after-tax dollars up to the §415 limit ($72,000 minus employee deferrals and employer contributions), then immediately converts the after-tax amount to Roth (with only the earnings being taxable). This requires a plan document that specifically permits after-tax contributions and in-plan Roth conversions; not all providers offer this feature. ## Frequently Asked Questions What is the Solo 401(k) contribution limit for 2026? The 2026 Solo 401(k) total limit is $72,000 (Section 415). This combines employee elective deferrals ($24,500, plus age 50+ catch-up of $8,000 or ages 60-63 catch-up of $11,250) and employer profit-sharing (up to 25% of net SE income after SE tax deduction, effectively ~20% of gross SE profit). For someone with $100,000 net SE profit: ~$18,587 employer plus $24,500 employee = $43,087 total. Source: IRS Notice 2025-67; IRC Section 415. Who is eligible for a Solo 401(k)? Self-employed individuals and business owners with no employees other than a spouse. Sole proprietors, LLC owners, S-corp owner-employees, and partners may participate. The business spouse may participate if employed by the business. If a non-spouse employee works 1,000+ hours in a plan year, the plan must convert to a full ERISA 401(k). Generally it must be established by December 31 of the applicable tax year, though a sole proprietor with no employees can adopt one after year end, by the tax filing deadline without extensions. Source: IRC Section 401(a); IRS Publication 560. How does a Solo 401(k) compare to a SEP IRA for self-employed individuals? Both allow up to $72,000 total in 2026, but the Solo 401(k) allows employee elective deferrals ($24,500) on top of employer contributions. At lower income levels (e.g., $50,000 net SE income), the Solo 401(k) allows far more total contributions (~$33,793 vs. ~$9,293 in a SEP IRA). The Solo 401(k) also allows Roth contributions and potential mega backdoor Roth. The SEP IRA requires no plan document and is simpler. Source: IRS Publication 560. ## References - [IRS: One-Participant 401(k) Plans](https://www.irs.gov/retirement-plans/one-participant-401k-plans) - [IRS Publication 560: Retirement Plans for Small Business](https://www.irs.gov/publications/p560) - [IRS: COLA Increases for Dollar Limitations](https://www.irs.gov/retirement-plans/cola-increases-for-dollar-limitations-on-benefits-and-contributions) **[Swoopr Editorial Team](https://www.getswoopr.com/authors/swoopr-editorial-team/)** The Swoopr Editorial Team produces sourced investment education content for independent investors. This profile cites IRS primary sources verified as of September 2026. See our [editorial policy](https://www.getswoopr.com/legal/editorial-policy/) and [corrections policy](https://www.getswoopr.com/legal/corrections-policy/).