401k Contribution Limits for Self-Employed

If you work for yourself, a solo 401(k) (also called an individual or one-participant 401(k)) lets you contribute twice: once as the employee and once as the employer. That stacking is why it beats most other retirement accounts for freelancers, consultants, and owner-only businesses.

Short answer for 2026: you can defer up to $24,500 as the employee, add an employer contribution of about 20% of net self-employment earnings (25% of W-2 pay if you run an S-corp), and the two combined cannot exceed $72,000. Catch-up contributions go on top: $8,000 at age 50+, or $11,250 if you are 60 to 63 at year-end. These figures are from IRS Notice 2025-67 and the IRS announcement 401(k) limit increases to $24,500 for 2026.

Solo 401(k) contribution limits for 2026

For comparison, the 2026 IRA limit is $7,500 ($8,600 at 50+). A solo 401(k) can shelter nearly ten times as much. If you are an employee in a workplace plan rather than self-employed, the 401(k) and IRA contribution limits guide covers deferrals across multiple employers, the Roth catch-up rule and IRA income limits.

In 2025 the deferral limit was $23,500, the catch-up was $7,500, and the total-additions cap was $70,000. If you set up automatic contributions last year, raise them — the limits do not adjust your elections for you.

How the employee and employer contributions work

The employee deferral

As the employee, you can defer up to $24,500 of earned income (or 100% of it, if less). Most plans let you choose traditional (pre-tax) or Roth (after-tax) deferrals, or split between them.

The deferral limit follows you, not the business. If you also defer $15,000 into a 401(k) at a W-2 job in 2026, you have only $9,500 of deferral room left for your side business. Over-deferring across plans is the most common solo 401(k) error; the excess has to be withdrawn by April 15 of the following year or it is taxed twice.

The employer contribution

As the employer, the plan can contribute up to 25% of "compensation." For a sole proprietor or single-member LLC, compensation is net profit minus half of self-employment tax and minus the employer contribution itself. That circular definition works out to an effective rate of 20% of net profit after the half-SE-tax deduction. IRS Publication 560 has the rate table and worksheet.

If your business is taxed as an S-corporation, the math is simpler: the employer contribution is up to 25% of the W-2 wages the company pays you. Distributions do not count. This is a real trade-off when you set your salary — see the S-corp payroll tax calculator to weigh payroll tax against retirement room.

The combined cap

Employee deferrals plus employer contributions cannot exceed $72,000 (catch-ups excluded). Once you hit that, the employer piece is what gets trimmed.

Worked examples with 2026 numbers

Each example uses a sole proprietor filing Schedule C. Self-employment tax is 15.3% of 92.35% of net profit, with the 12.4% Social Security part stopping at the 2026 wage base of $184,500.

Example 1 — freelancer, age 35, $80,000 net profit

• SE tax: $80,000 × 0.9235 = $73,880 × 15.3% = $11,303.64. Half is $5,651.82.
• Adjusted earnings: $80,000 − $5,651.82 = $74,348.18
• Employer contribution: $74,348.18 × 20% = $14,869.64
• Employee deferral: $24,500
• Total: $39,369.64

Example 2 — consultant, age 42, $150,000 net profit

• SE tax: $150,000 × 0.9235 = $138,525 × 15.3% = $21,194.33. Half is $10,597.16.
• Adjusted earnings: $139,402.84 × 20% = $27,880.57 employer
• Employee deferral: $24,500
• Total: $52,380.57

Example 3 — business owner, age 55, $300,000 net profit

• SE tax: Social Security on $184,500 × 12.4% = $22,878, plus Medicare on $277,050 × 2.9% = $8,034.45, total $30,912.45. Half is $15,456.23.
• Adjusted earnings: $284,543.77 × 20% = $56,908.75 — but the employer piece is capped at $72,000 − $24,500 = $47,500
• Employee deferral $24,500 + catch-up $8,000
• Total: $80,000

At age 61 the same owner could put in $83,250 because the age 60–63 catch-up replaces the $8,000 one.

Example 4 — S-corp owner, age 45, $100,000 W-2 salary

• Employer contribution: 25% × $100,000 = $25,000
• Employee deferral: $24,500 (withheld through payroll)
• Total: $49,500

Notice the pattern: at lower incomes the employee deferral does most of the work, which is why a solo 401(k) beats a SEP IRA until profit is very high. Run your own numbers in the solo 401(k) calculator.

The Roth catch-up rule for high-earning S-corp owners

Starting in 2026, SECURE 2.0 requires catch-up contributions to be made as Roth if your prior-year FICA wages from the employer sponsoring the plan exceeded $150,000.

This matters mostly for S-corp owners who pay themselves a large salary: if your 2025 W-2 from your S-corp exceeded $150,000, your 2026 catch-up must go in as Roth. A sole proprietor or partner has no FICA wages from the business — self-employment income is taxed under SECA instead — so the mandatory-Roth rule does not reach their catch-ups.

Traditional or Roth: how to choose

A pre-tax deferral cuts this year's taxable income. A $24,500 traditional deferral saves $5,390 of federal income tax at the 22% bracket, or $7,840 at 32%. A Roth deferral saves nothing now but comes out tax-free later.

A practical rule: if your 2026 taxable income lands in the 10% or 12% bracket (up to $50,400 single or $100,800 joint), Roth deferrals usually win; if you are in the 32% bracket or above, pre-tax usually wins. In between, splitting hedges against future rate changes.

Two details people miss:

• Neither choice reduces self-employment tax. SE tax is computed on net profit before retirement contributions. Only income tax drops.
• Contributions shrink your QBI deduction. The deduction for your solo 401(k) contributions reduces qualified business income, so a $20,000 employer contribution lowers your 20% QBI deduction by up to $4,000. Model both in the QBI deduction calculator.

SECURE 2.0 also allows employer contributions to be designated Roth if the plan document permits it. Many solo 401(k) providers have not added the option, and Roth employer contributions are taxable income in the year they are made.

Deadlines for the 2026 tax year

• Opening a brand-new plan: a sole proprietor with no employees can adopt a solo 401(k) as late as the tax-filing deadline (April 15, 2027, for most people) and still make both employee deferrals and employer contributions for 2026. The deferral part of this rule applies only to the plan's first year.
• Existing plan, deferral election: make your written deferral election by December 31, 2026. A sole proprietor can deposit the money after year-end once net profit is known, up to the filing deadline. S-corp owners defer through payroll, so deposits follow each paycheck.
• Employer contribution: due by your business's tax-filing deadline, including extensions — October 15, 2027, for an extended 2026 Schedule C return.
• Form 5500-EZ: required once plan assets exceed $250,000 at the end of the plan year (and in the plan's final year). For a calendar-year plan it is due July 31 of the following year.

Because contributions can be made after year-end, you can wait until your Schedule C is done and contribute the exact maximum. Just remember to count planned contributions when you size your quarterly payments — the quarterly estimated tax guide covers safe-harbor amounts.

Solo 401(k) vs other self-employed retirement plans

With the 20% employer rate, a sole proprietor's SEP needs about $376,000 of net profit to reach $72,000; the solo 401(k) gets there at roughly $252,000 because the $24,500 deferral comes first. Below that, the solo 401(k) always allows more.

The main reason to pick a SEP is employees. A solo 401(k) is only for the owner and a spouse who works in the business. Hire an eligible employee and the plan has to cover them, which usually means converting to a standard 401(k).

Ways to raise your total

1. Add your spouse. A spouse who earns compensation from the business can have a separate $24,500 deferral, catch-up, and employer contribution in the same plan.
2. Time large expenses. Because the employer piece is 20% of net profit, pulling a $10,000 equipment purchase into this year costs about $2,000 of contribution room. If maxing out matters more, it can make sense to defer the purchase.
3. Use the 60–63 window. Four years at the higher $11,250 catch-up adds $13,000 more than the regular catch-up over the same period.
4. Stack an HSA. If you have a high-deductible health plan, the 2026 HSA limit is $4,400 self-only or $8,750 family, deductible on top of your solo 401(k). See the HSA calculator.
5. Go backdoor for the IRA. If your income is above the Roth IRA limits, a nondeductible traditional IRA converted to Roth still works. Keeping pre-tax IRA balances in the solo 401(k) rather than a rollover IRA avoids the pro-rata rule; the backdoor Roth calculator shows the effect.

Common mistakes to avoid

• Using 25% of net profit. For sole proprietors the effective employer rate is 20% of net profit after half of SE tax. Using 25% creates an excess contribution.
• Forgetting other plans. The $24,500 deferral is per person across every employer. Check your W-2 job's year-to-date deferrals before funding the side business plan.
• Missing the Form 5500-EZ filing once assets pass $250,000. Late filing triggers per-day penalties, though the IRS has a reduced-penalty late-filer program.
• Adding employees without amending the plan. A solo 401(k) only works when the owner (and spouse) are the only participants who meet the eligibility rules.
• Counting catch-ups toward the $72,000 cap. They sit on top of it, so a 55-year-old can reach $80,000.

Bottom line

For 2026, a self-employed person can put up to $72,000 into a solo 401(k) — $80,000 at 50+, $83,250 at 60 to 63 — by combining a $24,500 employee deferral with an employer contribution of about 20% of net earnings. The exact amount depends on your profit, so finish your Schedule C numbers, plug them into the solo 401(k) calculator, and compare the result against your expected tax using the 1099 tax calculator. The 1099 tax guide for independent contractors covers the rest of the self-employed tax picture.

Employee elective deferrals in a solo 401(k) can also count toward the federal Saver's Match for tax years beginning after 2026. Count only the employee piece, not employer profit-sharing, and note that the match cannot go into a Roth account. The Saver's Match guide covers the income phase-outs and the distribution lookback.