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Free solo 401(k) contribution calculator for self-employed retirement — elective deferrals, employer sharing, and Section 415 room—not a substitute for a CPA.
Last updated: April 18, 2026
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Schedule C–style profit after expenses, before retirement contributions (illustrative)
Total contributions (employee + employer)
$53,186.03
Max elective cap (with catch-up if checked): $24,000
Notes
IRS cap
Catch-up optional
Capped by compensation and the published deferral limit.
20% style
After ½ SE tax
Common self-employed formulation tied to net profit.
½ deduction
Estimated
Social Security and Medicare components modeled for the deduction.
Ceiling
Combined cap
Shows remaining room after employee + employer.
Not S-corp W-2
Different if W-2
S-corporation compensation follows payroll-based rules.
Disclaimer
Illustrative
Plan documents and IRS forms control actual contributions.
Default: $185,000 net profit, $23,500 employee deferral, 2026 limits, under age 50:
Illustrative total contributions
~$53,186
We start from your net self-employment profit, estimate the deductible half of self-employment tax using Social Security (up to the wage base) and Medicare components on 92.35% of net earnings, then cap your employee deferral by the IRS elective limit (plus catch-up if selected) and by available compensation. Employer profit-sharing is estimated with the common 20% of adjusted net shortcut that corresponds to the self-employed 25%-of-compensation rule, then limited so employee + employer ≤ Section 415(c) for the year.
½ SE tax ≈ f(92.35% × net profit, SS wage base)Allowed deferral = min(elective cap, net − ½ SE tax)Employer ≈ min(20% × (net − ½ SE tax − deferral), 415 − deferral)Rounding and plan-specific definitions can change dollars—use your adoption agreement and tax forms for final numbers.
Raise net profit or toggle age 50+ to see cap changes
Also see our 457(b) retirement calculator for public-sector deferrals.
Get a Custom CalculatorIf you also have W-2 income elsewhere, coordination rules may apply—this model is single-business focused.
Not tax or legal advice; for education and estimation only.
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