Solo 401(k) & SEP-IRA Calculator

How much can you actually put away as a self-employed owner?

A quick 2025 tax year estimate for Solo 401(k) and SEP-IRA contribution limits — including the SECURE 2.0 super catch-up for ages 60–63.

This is a planning tool, not tax advice. The output is an estimate based on 2025 IRS limits and the inputs you provide. Contribution limits change annually and the actual number you can deduct depends on your entity structure, plan document, W-2 wages, self-employment tax, other retirement plans you (or a controlled group) sponsor, employee coverage, and other facts specific to your business. Consult a CPA before adopting a plan or making a contribution. See our Business Management and Taxation pages, or request a consultation.
Business structure

The math changes materially between a Schedule C sole prop and an S-corp W-2 owner.

Pick a business structure.

For Schedule C or partnership K-1: your net profit before any retirement contribution or ½ SE tax deduction. For S-corp or C-corp: your W-2 Box 1 wages from the business.

Enter an amount of 0 or more (max 10,000,000).

Drives the catch-up tier. 50+ adds $7,500. Ages 60–63 get the SECURE 2.0 super catch-up of $11,250. At 64+ the catch-up drops back to $7,500.

Enter an age between 18 and 99.

Do you have employees other than yourself (and spouse)?

Solo 401(k) is only for owner-only businesses (spouse is fine). If you have W-2 employees, Solo 401(k) is off the table; SEP-IRA still works but you must contribute the same % of comp for every eligible employee.

Pick one.

Which plan are you looking at?

Pick a plan.

The $23,500 employee elective deferral limit is per-person, not per-plan. If you also contribute to a W-2 employer's 401(k), that eats into what you can defer into your Solo 401(k). Enter total, or leave blank/0.

Enter 0 or more (max $23,500).

Estimated maximum contribution

ComponentAmount

Estimated tax savings (traditional / pre-tax)

Pick your marginal federal rate. Multiply your pre-tax contribution by the rate to see the tax savings.

How this was calculated

This is an estimate — not tax advice.

Actual contribution limits depend on your plan document, elective deferrals to any other 401(k), §415(c) aggregation rules across controlled-group plans, whether your plan permits Roth, employee coverage testing, catch-up eligibility timing, and IRS COLA adjustments each year. A CPA should confirm the number before you fund the plan.

Talk to a CPA about your retirement plan →

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2025 contribution limits at a glance

Age tier Employee deferral (401k) Catch-up Total §415(c) limit SEP-IRA cap
Under 50$23,500—$70,000$70,000
50–59$23,500$7,500$77,500$70,000
60–63 (SECURE 2.0)$23,500$11,250$81,250$70,000
64+$23,500$7,500$77,500$70,000

Compensation cap for both plans: $350,000 (§401(a)(17)). SEP-IRA does not permit employee deferrals or catch-ups. Roth SEP-IRA is not available.

Want the full rules?

Get the SECURE 2.0 rules summary and the 2025/2026 contribution limits table by email.

We'll send you a one-page PDF that covers the SECURE 2.0 changes (super catch-up, Roth employer contributions, mandatory Roth catch-up for high earners in 2026), the 2025 and 2026 IRS limits side-by-side, and the deadline / plan-adoption checklist. Email only — no phone, no firm size, nothing else.

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© Laléa & Black, LLP. 2025 IRS contribution limits per Notice 2024-80 and SECURE 2.0 Act of 2022. This tool is directional and does not account for controlled-group aggregation, coverage testing under §410(b), top-heavy rules, ACP/ADP testing, plan document restrictions, or state tax treatment. This tool does not create a client relationship, is provided "as-is" without warranty, and does not constitute tax, legal, or accounting advice.