Solo 401(k) Contribution Calculator 2026

2026 tax year

Find the most you can put into a Solo 401(k) for 2026: employee deferral, catch-up and employer contribution shown separately, for a sole proprietor or an S corp owner, with or without a 401(k) at another job.

Try an example

Your Solo 401(k) contribution

Most you can contribute

Employee deferral: $0
Employer contribution: $0
Employee plus employer: $0
Catch-up (on top of the limit): $0
Total: $0

How the numbers are figured

This calculator gives a general estimate for educational purposes only. It isn't personalized financial or tax advice. It covers one Solo 401(k) for a sole proprietor, single-member LLC or S corp owner, and doesn't cover every situation: several businesses, a spouse's own contributions, plan-specific rules or prior-year corrections. The 60 to 63 catch-up applies only if your plan allows catch-up contributions. Confirm your actual limit with a CPA or your plan provider before contributing. Read the full Financial Disclaimer.

What this calculator estimates

A Solo 401(k) lets you contribute twice: once as the employee and once as the employer. The calculator finds the most each part allows for 2026 and adds them up, with catch-up contributions shown on their own line because they sit on top of the overall limit.

Employee deferral: up to $24,500 for 2026, and never more than you earned. The limit is shared with any 401(k) or 403(b) at another job.
Employer contribution for a sole proprietor or single-member LLC: 20% of your net profit minus half of your self-employment tax. The IRS uses 20% instead of 25% because your own contribution is paid out of the profit it's figured on.
Employer contribution for an S corp owner: 25% of the W-2 salary the corporation pays you. Distributions don't count.
Plan limit: employee deferral plus employer contribution can't exceed $72,000, or 100% of your compensation if that's lower. Pay above $360,000 isn't counted.
Catch-up: $8,000 extra at 50 or older, or $11,250 if you turn 60, 61, 62 or 63 this year (it replaces the $8,000). It sits on top of the $72,000, so the most one plan can take is $80,000 at 50 or older and $83,250 at 60 to 63.

All 2026 limits come from IRS Notice 2025-67. For the tax side, a Traditional contribution lowers income tax but not self-employment tax, as this guide explains. To compare the plan with a SEP IRA and see the tax it saves, use the Solo 401(k) vs SEP IRA calculator.

Examples

Each row was run through this calculator at the maximum. A sole proprietor, no other plan, unless the row says otherwise.

Situation	Employee	Employer	Catch-up	Total
$50,000 profit, under 50	$24,500	$9,293	$0	$33,793
$100,000 profit, under 50	$24,500	$18,587	$0	$43,087
$150,000 profit, under 50	$24,500	$27,881	$0	$52,381
$300,000 profit, under 50	$24,500	$47,500	$0	$72,000
$300,000 profit, age 55	$24,500	$47,500	$8,000	$80,000
$300,000 profit, age 61	$24,500	$47,500	$11,250	$83,250
$100,000 profit, $20,000 already deferred at a day job	$4,500	$18,587	$0	$23,087
S corp, $80,000 W-2 salary	$24,500	$20,000	$0	$44,500

Frequently asked questions

How much can I contribute to a Solo 401(k) in 2026?

As the employee, up to $24,500, shared with any other 401(k) you have. As the employer, 20% of your net profit after half of self-employment tax (25% of W-2 salary for an S corp owner). Employee plus employer can't exceed $72,000, and catch-up contributions come on top: $8,000 at 50 or older, or $11,250 at 60 to 63. The most one plan can take in is $80,000, or $83,250 at 60 to 63.

How is the employer contribution figured for a sole proprietor?

Start with your net profit, subtract half of your self-employment tax, and multiply by 20%. The IRS uses 20% rather than 25% because your own contribution comes out of the same profit it's figured on. For an S corp owner, the employer contribution is 25% of the W-2 salary the corporation pays you, and K-1 distributions don't count.

Does the catch-up count toward the $72,000 limit?

No. The $72,000 limit covers your employee deferral plus the employer contribution. Catch-up contributions sit on top of it, which is how the total can reach $80,000 at 50 or older and $83,250 at 60 to 63. They still can't exceed what you earned.

What if I also have a 401(k) at a W-2 job?

The $24,500 employee limit, and the catch-up, are shared across every 401(k) or 403(b) you defer into, so what you put in at work reduces your room in the Solo 401(k). The employer contribution is separate: the $72,000 limit applies to each unrelated employer's plan on its own. Enter what you've deferred at work in the calculator.

Do I have to defer the maximum?

No. Enter an amount in the planned deferral field and the calculator shows your employer room and total with that deferral. The employer contribution for a sole proprietor is limited by the 20% rate, not by how much you defer, so deferring less doesn't raise it unless the overall limit was the constraint.

Solo 401(k) Contribution Limits for 2026: every limit explained, with examples by income
Solo 401(k) vs. SEP IRA: which plan holds more at your income
Solo 401(k) and a 401(k) at Work: how to split the $24,500
Can My Spouse Join My Solo 401(k)?: a second set of contributions
Does a Solo 401(k) Reduce Self-Employment Tax?: why it only lowers income tax
Do I Need an EIN for a Solo 401(k)?: setting the plan up
Solo 401(k) for Real Estate Agents: a worked example on $80,000 of profit
SEP IRA and Solo 401(k) Deadline: when contributions have to be made
SEP IRA and a 401(k) at the Same Time: what the limits do when you have both

More tools

Solo 401(k) vs SEP IRA calculator: both plans side by side, with the tax your contribution saves
Freelance tax calculator: the tax a retirement contribution lowers
S corp savings calculator: salary and payroll tax for S corp owners

Sources

The official, primary sources behind the figures and rules on this page.