Most you can put in a solo 401(k) for 2026 or 2025: deferral, employer share and catch-up
Estimates only, not financial advice. What you type stays on your device. Checked against sources on 30 Oct 2026.A solo 401(k) for 2026 takes a $24,500 employee deferral plus an employer share of 20% of net self-employment earnings, or 25% of W-2 pay, up to $72,000 in total. On $100,000 of net profit at age 45 that is $43,087.04: $24,500 plus $18,587.04. Catch-up adds $8,000 from age 50, or $11,250 at 60 to 63.
Rates and rules read from the sources listed on this page (the earliest on 30 Oct 2026); they may have changed since.
Pick the "Tax year", 2026 or 2025, and under "How you are paid" choose self-employed or W-2 salary.
Enter your net profit from Schedule C or K-1, or your "W-2 wages, box 5" if you are paid a salary.
Enter your age on December 31 and any "Deferrals already made at another job".
Read "Total you can contribute", split into "Employee deferral", the employer share and "Catch-up".
Press "Share result" to copy a link with these inputs.
A solo 401(k), also called an individual or one-participant 401(k), covers a business owner with no employees other than a spouse. You contribute twice: once as the employee, through elective deferrals, and once as the employer, through a profit-sharing contribution. This calculator works out the most you can put in for 2026 or 2025.
The limits, from IRS Notice 2025-67. For 2026, elective deferrals are capped at $24,500 ($23,500 for 2025). Deferrals and the employer share together are capped at $72,000 ($70,000 for 2025) and at 100% of your compensation, with pay above $360,000 ($350,000) ignored. Catch-up contributions sit on top: $8,000 at 50 or over ($7,500 for 2025), or $11,250 if you turn 60, 61, 62 or 63 during the year.
Self-employed. For a sole proprietor or partner the employer share is 20% of net earnings from self-employment, meaning net profit less the deduction for half your self-employment tax. The calculator figures that tax the way Schedule SE does (92.35% of profit, 12.4% up to the $184,500 wage base for 2026, 2.9% on all of it) and then runs the Publication 560 Deduction Worksheet for Self-Employed, step by step.
Paid a W-2 salary. An S or C corporation owner contributes from salary: the company adds up to 25% of W-2 pay. Profit passed through on a K-1 does not count.
Other plans. The deferral limit is per person, so deferrals at another job reduce the room here. For 2026, if your 2025 wages from the sponsoring employer were above $150,000, catch-ups must be Roth.
What this does not do: plans with employees, defined benefit plans, or the tax you save. An estimate, not tax advice.
For 2026 the combined limit on elective deferrals and employer contributions is $72,000, and deferrals alone are capped at $24,500, according to IRS Notice 2025-67. Catch-up contributions are added on top: $8,000 at age 50 or over, or $11,250 for anyone turning 60, 61, 62 or 63 during 2026.
A sole proprietor's employer share is 20% of net earnings from self-employment, which is net profit less the deduction for half of self-employment tax. The 20% comes from the Publication 560 rate table: a 25% plan rate divided by 1.25. The calculator shows every worksheet step.
Under SECURE 2.0, a person who reaches age 60, 61, 62 or 63 during the year can make a larger catch-up contribution: $11,250 for both 2025 and 2026, instead of $8,000 in 2026. From age 64 the ordinary catch-up for those 50 or over applies again.
Yes, but the $24,500 elective deferral limit for 2026 is per person across all 401(k) and 403(b) plans. Deferrals made at your job reduce what you can defer to the solo plan. The employer share from your own business is separate, subject to its own limits.
An S corporation owner contributes from W-2 salary only. The company can contribute up to 25% of that salary, and the owner defers up to the annual limit, all within the $72,000 total for 2026 and 100% of pay. Distributions of profit on the K-1 do not count as compensation.
For 2026, catch-up contributions must be designated Roth if your 2025 wages from the employer sponsoring the plan were above $150,000, the threshold in IRS Notice 2025-67. Check how your plan provider applies the rule to your situation, especially if you are self-employed without W-2 wages.
Rates and rules change; check the source before you rely on a figure.
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