What is the Solo 401(k) contribution limit for 2026?

For 2026 the employee elective deferral cap is $23,500. The combined employee + employer limit is $70,000. Add $7,500 if you are 50 or older, or $11,250 if you are between 60 and 63 (the SECURE 2.0 super catch-up). That puts the all-in ceiling at $77,500 or $81,250.

Can I open a Solo 401(k) with no employees?

Yes, that is the entire point. A Solo 401(k) is for owner-only businesses (sole prop, single-member LLC, partnership of spouses, or S-corp where the owner is the only common-law employee). The moment you hire a non-spouse W-2 employee who works 1,000+ hours, the plan no longer qualifies.

Solo 401(k) vs SEP IRA, which lets me contribute more?

At low and mid incomes, Solo 401(k) wins because you get the $23,500 employee deferral on top of profit sharing. SEP IRA only allows the 25% / 20% employer share. Both plans hit the same $70,000 cap at high incomes, so beyond about $350,000 of net SE earnings the difference flattens out. Solo 401(k) also allows Roth and loans.

How is the employer share calculated for a sole proprietor?

The IRS uses 25% of net self-employment earnings, but because the contribution itself is deductible the effective rate works out to about 20% of net earnings (which is your Schedule C profit times 92.35%). Our calculator runs that math for you.

Is the deadline to set up a Solo 401(k) the end of the year?

The plan must exist by your tax filing deadline including extensions to count for that tax year (SECURE Act 2019 change). Employee deferrals for sole props can be made up to the unextended due date, while employer profit sharing has until the extended deadline.

Can I contribute to both a Solo 401(k) and a regular 401(k) at a day job?

Yes, but the $23,500 elective deferral limit is per person across all 401(k) plans, not per plan. The $70,000 combined limit is per unrelated employer. So you can max your day-job 401(k) employee deferral, then add employer profit sharing on the Solo 401(k) side from your self-employment income.

Solo 401(k)·Calculator

Solo 401(k), Without the Spreadsheet.

Punch in your self-employment income. See your max contribution, tax savings, and a 30-year balance, in 2026 limits.

$23,500 deferral·$70,000 combined·$11,250 super catch-up

For 2026, a Solo 401(k) lets a self-employed person contribute up to $23,500 as employee deferral plus up to 25 percent of W-2 wages or about 20 percent of net self-employment income as employer profit sharing. The combined cap is $70,000, or $77,500 if you are 50 to 59, or $81,250 if you are 60 to 63 thanks to the SECURE 2.0 super catch-up. The plan must be set up by your tax filing deadline including extensions.

2026 IRS limits

Combined cap $70,000

Business type

Net self-employment income (or W-2 wages)

After business expenses. We back out half of self-employment tax for you.

Age in 2026

50+ opens $7,500 catch-up. 60–63 opens the $11,250 super catch-up.

Elective deferral you want to make

Capped at $23,500 (or $31,000 / $34,750 with catch-up). Set to your max if you want.

Marginal federal tax rate

Pick your top bracket. We use it for the traditional pre-tax savings line.

Annual return assumption