What are the solo 401(k) limits for 2026 and 2027?

The short answer

In 2026 the most that can go into one person's solo 401(k), before catch-up, is $72,000. Catch-up adds $8,000 at age 50 or older, or $11,250 if you turn 60, 61, 62, or 63 in 2026. For 2027, Milliman and Marsh forecast $75,000 of annual additions. The IRS had not published 2027 retirement plan limits as of October 22, 2026.

A solo 401(k) is the IRS one-participant 401(k): a regular 401(k) for an owner with no employees other than the owner and a spouse. The owner can contribute twice, once as the employee and once as the employer.

What are the 2026 limits, and what is only a 2027 forecast?

The 2026 column is from the IRS COLA table and Notice 2025-67. The notice states that the Roth catch-up wage threshold used for 2026 catch-up contributions rose from $145,000 to $150,000. That $150,000 is prior-year wages from the employer that sponsors the plan, not the 2026 highly compensated employee threshold, which the same COLA table lists at $160,000.

The 2027 column is Milliman's October 15, 2026 final forecast, which matches the figures Marsh published the same day, including a $155,000 Roth catch-up wage threshold. Treat every 2027 cell as a forecast until the IRS notice for 2027 is out. A shorter note on the same forecast is solo 401(k) limits, the 2027 forecast.

How is the employer contribution figured?

For an S corporation or C corporation owner, the company can generally contribute up to 25 percent of W-2 pay from that company. The employee deferral counts against the $72,000 annual additions limit. Catch-up sits on top of it.

For a sole proprietor or a partner, compensation is net earnings from self-employment after the deduction for half of self-employment tax and for the contribution itself. The rate table in Publication 560, Chapter 5, is the one to use. The effective rate is lower than 25 percent of profit, so the wage figure below does not apply to a Schedule C owner.

How much W-2 salary fills the cap?

This is a hypothetical for Dana, the sole owner of an S corporation, and it is for illustration only. It is not a statement of what Dana's salary should be. Reasonable compensation comes first. See what a reasonable S corp salary is.

To fill the annual additions limit with a full employee deferral, the company's share has to cover the gap:

Check the division. $47,500 divided by 0.25 is $190,000. $49,500 divided by 0.25 is $198,000. If Dana defers less than the maximum, the employer share, and the wages needed to support it, change.

In 2027 the Social Security wage base is $192,300, the figure on the SSA fact sheet for 2027. Wages above that base owe Medicare tax and not Social Security tax. A salary chosen only to fill a retirement plan can still fail the reasonable-compensation test if it does not match the work.

When do catch-up contributions have to be Roth?

Under the SECURE 2.0 rule that Notice 2025-67 applies for 2026, if prior-year wages from the sponsoring employer are over the $150,000 threshold, catch-up contributions generally have to be designated Roth. If the plan does not offer Roth, the catch-up may not be available. Owners with no FICA wages from the sponsor are treated differently under the regulations. That is a question for the plan administrator, not a default.

Milliman forecasts $155,000 as the threshold that would apply to 2027 catch-ups. That cell is a forecast.

What other rules do owners run into?

Hiring employees generally ends the one-participant plan. Eligible employees have to be covered, and the plan is then subject to nondiscrimination testing unless it uses a safe harbor design.

Form 5500-EZ is generally required once a one-participant plan has $250,000 or more in assets at the end of the year. The IRS one-participant page states that filing rule.

Deferral limits are per person, not per plan. Deferrals to a second employer's 401(k) count against the same $24,500.

Some owners pair the 401(k) with a cash balance plan when the business can fund a larger benefit. The two plans are tested together. See cash balance plan limits by age and the owner retirement plan calculator.

North Carolina does not have its own 401(k) dollar cap. The federal limits above are the ones that apply to a North Carolina owner. State tax on the wages, and on a later distribution, is a separate return question for your CPA.

The bottom line

For 2026, the IRS number is $72,000 before catch-up, with $24,500 of that available as an employee deferral, and an S corporation generally needs $190,000 of W-2 pay to fill the rest at 25 percent. The 2027 column, $75,000 and a $198,000 salary, is a published forecast from Milliman and Marsh, not an IRS limit. Salary still has to be reasonable for the job before any of those percentages matter.

If you set the salary only to hit the cap, would the pay still look reasonable for the work you actually do?

The payroll-tax cost of the wage that fills the cap is on the S corp salary that fills a solo 401(k). Run the 2026 limits in the owner retirement plan calculator, or a sale through the business sale calculator. Durham owners can start from the financial advisor in Durham, NC page. The owner lessons hold the longer path.

Questions people ask next

Is the 2027 solo 401(k) limit official?

No. As of October 22, 2026 the IRS had not published 2027 retirement plan limits. The 2027 column on this page is the Milliman and Marsh forecast from October 15, 2026, based on inflation data, and it will be replaced when the IRS announces the real limits.

Do catch-ups count toward the $72,000?

No. The $72,000 defined contribution limit for 2026 is the annual additions cap under Section 415(c). Catch-up contributions sit on top of that cap. The IRS describes the 2026 cap as $72,000, or $80,000 with the age-50 catch-up, or up to $83,250 at ages 60 to 63.

Can my spouse be in my solo 401(k)?

Yes. The IRS one-participant 401(k) covers a business owner with no employees other than the owner and a spouse. Each person has a separate limit based on that person's own compensation.

What salary fills the 2026 cap for an S corporation?

After a $24,500 employee deferral, the employer share needed to reach $72,000 is $47,500. At 25 percent of W-2 pay, that is $190,000 of wages. The salary still has to be reasonable pay for the work, which is a separate test.