Solo 401(k) contribution calculator
A solo 401(k) lets a self-employed owner contribute twice: up to $24,500 as the employee for 2026, plus an employer share of about 20% of net profit, or 25% of W-2 pay in an S-Corp. The total caps at $72,000, plus catch-up from age 50. A SEP IRA allows only the employer share.
Updated November 2026
Calculator
2026 limits: $24,500 deferral, $72,000 total, $360,000 pay cap, catch-up $8,000 or $11,250 at 60 to 63. If your W-2 pay from the business was over $150,000 last year, catch-ups have to go in as Roth. An estimate, not plan advice. An estimate, not tax advice.
How much can I put in a solo 401(k) for 2026?
| Limit | 2026 |
|---|---|
| Employee deferral | $24,500 |
| Catch-up, age 50 to 59 or 64 and up | $8,000 |
| Catch-up, age 60 to 63 | $11,250 |
| Total of employee and employer, before catch-up | $72,000 |
| Pay counted, at most | $360,000 |
The employer share is 25% of W-2 wages for an S-Corp owner. For a sole proprietor or single-member LLC it works out to about 20% of net profit, because you first subtract half of your self-employment tax.
Solo 401(k) or SEP IRA?
A SEP IRA only allows the employer share, so at most incomes a solo 401(k) lets you save more, thanks to the $24,500 deferral. A SEP is simpler to set up and run. The solo 401(k) also allows Roth contributions and, in many plans, loans. Once a solo 401(k) holds more than $250,000, it files Form 5500-EZ each year. Our post on solo 401(k) vs SEP IRA compares them side by side.
When do I have to set it up?
Set up a solo 401(k) well before year end. Employee deferrals have their own timing rules, while the employer share can be made up to your tax filing deadline, including extensions. A SEP IRA can be opened and funded up to the filing deadline, including extensions. Run the S-Corp calculator too, because your salary as an S-Corp owner sets the employer share.
Sources
General information, not tax advice for your situation.
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See our tax planning and CFO serviceWhat is the solo 401(k) limit for 2026?
$72,000 of combined employee and employer contributions, plus catch-up of $8,000 from age 50, or $11,250 at ages 60 to 63.
Can I have a solo 401(k) if I have a W-2 job too?
Yes. But the $24,500 employee deferral is shared across all your 401(k) plans, so contributions at your job reduce it.
Can my spouse join my solo 401(k)?
Yes, if your spouse works in the business and is paid. A solo 401(k) is for owners and their spouses with no other full-time employees.
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