💼 Solo 401(k): Calculator (2026)

Find your maximum 2026 Solo 401(k) contribution as a self-employed business owner — employee deferral plus employer profit-sharing.

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Age
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MAXIMUM TOTAL 2026 CONTRIBUTION
$0
Employee + Employer combined
Employee Deferral (Used)
$0
Max Employer Contribution
$0
Overall 415(c) Limit (Your Age)
$0
Room Remaining
$0

How Solo 401(k) Contributions Work

A Solo 401(k) lets a self-employed business owner with no full-time employees (other than a spouse) contribute in two capacities: as the "employee" (a salary deferral) and as the "employer" (a profit-sharing contribution) — letting you stack both well beyond what a SEP IRA or traditional IRA alone would allow.

2026 Solo 401(k) Limits

AgeEmployee DeferralOverall Combined Limit
Under 50$24,500$72,000
50-59 or 64+$32,500 (incl. $8,000 catch-up)$80,000
60-63 ("super" catch-up)$35,750 (incl. $11,250 catch-up)$83,250

Why the Employer Share Is ~20%, Not 25%, for Sole Proprietors

Net Earnings for Retirement = Net SE Income − (½ of Self-Employment Tax)
Max Employer Contribution = Net Earnings for Retirement × 20%

Corporations calculate the employer contribution as 25% of W-2 wages — simple. Sole proprietors and single-member LLCs don't have W-2 wages, and the plan's 25% contribution rate would otherwise need to be applied to earnings after subtracting the contribution itself — a circular calculation. The IRS resolves this with a simplified equivalent rate: 20% applied to your net earnings before the contribution (25% ÷ 125% = 20%), which produces the exact same result without the circularity. After also subtracting the deductible half of your self-employment tax, this works out to roughly 18.6% of your raw net self-employment income — a detail a lot of quick online estimates get wrong.

⚠️ Important: This calculator uses the standard simplified self-employment tax approximation (15.3% of 92.35% of net income, split in half for the deduction) and doesn't account for the Social Security wage base cap, the additional 0.9% Medicare surtax, or other above-the-line deductions that could affect your exact net earnings from self-employment. Consult a CPA or plan administrator to confirm your exact contribution limit before funding your account.

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❓ Frequently Asked Questions

What is a Solo 401(k)?
A Solo 401(k) (also called an individual 401(k)) is a retirement plan for self-employed people with no full-time employees other than a spouse. It lets you contribute both as the "employee" and as the "employer," allowing much higher total contributions than a SEP IRA or traditional IRA in many cases.
How much can I contribute to a Solo 401(k) in 2026?
For 2026, you can defer up to $24,500 as the "employee" (plus a $8,000 catch-up at age 50-59 or 64+, or an $11,250 "super catch-up" at age 60-63), plus an "employer" profit-sharing contribution of up to 25% of W-2 wages (corporations) or roughly 20% of net self-employment income (sole proprietors/single-member LLCs), up to an overall combined limit of $72,000 ($80,000 at 50-59/64+, $83,250 at 60-63).
Why is the employer contribution rate 20% instead of 25% for sole proprietors?
The 25%-of-compensation limit for corporations applies to W-2 wages. For a sole proprietor or single-member LLC, there's no W-2 wage — the calculation instead uses net self-employment earnings after subtracting the deductible half of self-employment tax, which works out to roughly 20% of net self-employment income rather than a clean 25%.
Is a Solo 401(k) better than a SEP IRA?
At lower self-employment income levels, a Solo 401(k) usually allows a higher total contribution than a SEP IRA, because the employee deferral portion isn't tied to a percentage of income. A Solo 401(k) can also allow Roth contributions and loans, which a SEP IRA cannot.
Can my spouse also contribute to my Solo 401(k)?
Yes — if your spouse works in the business and receives compensation from it, they can also make their own employee and employer contributions under the same plan, effectively doubling the household's potential contribution room.

🏆 About This Tool — Accuracy & Trust

🔒 Data Privacy: All calculations run entirely within your browser using JavaScript. Nothing you enter here is ever transmitted to our servers, stored, sold, or shared.

📐 Accuracy Note: 2026 contribution limits and catch-up figures are sourced from published IRS inflation-adjustment numbers. Results are estimates for informational purposes; consult a CPA or retirement plan administrator before funding your Solo 401(k).

📅 Last Updated: October 2026.

Created and maintained by , founder of Your Calculator Hub · Last updated . How we build and check our calculators. Results are estimates for general information, not professional advice.