2026 Solo 401(k) Contribution Limits: $72,000, $80,000 at 50+, and the $24,500 Deferral Explained with Three Incomes

The three numbers that matter in 2026

Every Solo 401(k) article you read this year should agree on three figures. If it does not, it is using last year's limits.

• •$24,500 is the 2026 employee elective deferral limit. This is the amount you can put in as the "employee" side of your own plan, and it can be pre-tax or Roth.
• •$72,000 is the 2026 total contribution limit, combining your deferral with the employer contribution your business makes on your behalf.
• •$80,000 is the total for someone who is 50 or older at any point in 2026, reflecting the age-50 catch-up on the deferral side.

A fourth number does the real work: the employer contribution. For an incorporated business that pays you W-2 wages, it is 25 percent of compensation. For a sole proprietor or single-member LLC filing Schedule C, it is effectively about 20 percent of net self-employment earnings after subtracting half of your self-employment tax. The reason for the difference is circular math: the contribution is deductible, and the deduction reduces the earnings the percentage is applied to. The Solo 401(k) for high earners page has a longer walk-through; the rest of this article works three incomes so you can see where you land.

Only 15 to 18 percent of self-employed people use a Solo 401(k) at all (https://www.solo401k.com/blog/solo401k-adoption-growth-statistics-usa), which is remarkable given that 5.6 million independents earned $100,000 or more in 2025 according to MBO Partners (https://www.mbopartners.com/blog/press/2025-state-of-independence-reveals-growing-talent-strategy-for-business). The most common reason people give is that the math looks intimidating. It is not.

Income one: $60,000 net Schedule C

Start with a rideshare driver, freelance designer, or contract nurse who nets $60,000 after expenses on Schedule C.

Self-employment tax. Net earnings times 92.35 percent gives $55,410 subject to SE tax. At 15.3 percent, SE tax is about $8,478. Half of that, $4,239, is the adjustment.

Adjusted earnings for the employer contribution. $60,000 minus $4,239 equals $55,761.

Employer contribution. Roughly 20 percent of $55,761 is about $11,150.

Employee deferral. Up to $24,500, well under your earned income.

Total for 2026. About $35,650, comfortably below the $72,000 ceiling. If this person is 50 or older, the deferral rises by the catch-up amount and the total rises with it.

Compare that to the $7,500 Roth IRA limit. The Solo 401(k) lets this earner shelter almost five times as much. At the same income, a SEP IRA would allow only the employer piece, about $11,150, because a SEP has no employee deferral component.

Income two: $150,000 net Schedule C

Now a consultant, physician doing locum tenens work, or software contractor netting $150,000.

Self-employment tax. Ninety-two point three five percent of $150,000 is $138,525. Social Security tax applies only up to the 2026 wage base, so the calculation splits: 12.4 percent on earnings up to the wage base plus 2.9 percent Medicare on all of it. SE tax comes to roughly $21,000 to $21,500 depending on the final wage-base figure, and the half-deduction is about $10,600.

Adjusted earnings. Approximately $139,400.

Employer contribution. About 20 percent, or roughly $27,900.

Employee deferral. $24,500.

Total for 2026. Roughly $52,400. Still under $72,000, so the ceiling is not the binding constraint at this income. The binding constraint is the 20 percent employer formula.

This is the income band where the Solo 401(k) most clearly beats the SEP. A SEP at $150,000 allows only the employer piece, around $27,900. The Solo 401(k) adds the $24,500 deferral on top, nearly doubling the shelter. It also lets you make the deferral portion Roth if you prefer tax-free growth to a current deduction.

Income three: $300,000 net Schedule C

Finally, a high earner: a surgeon in a private practice structured as a sole proprietorship, a senior contract engineer, or an owner-operator with a very good year.

Employer contribution. Twenty percent of adjusted earnings would be roughly $58,000, but the total contribution cannot exceed $72,000, and the employer piece is further capped by the compensation limit used in the calculation ($360,000 for 2026). With a $24,500 deferral, the employer contribution is limited to $47,500 so the total lands exactly at $72,000.

If 50 or older. The deferral rises by the catch-up amount, so the total ceiling becomes $80,000. The employer piece stays at $47,500 and the extra room is filled by the catch-up deferral.

At this income the Solo 401(k) and SEP converge on the same $72,000 ceiling for someone under 50, because 20 percent of adjusted earnings already exceeds it. The Solo 401(k) still wins for anyone 50 or older, because the SEP has no catch-up provision, and it wins for anyone who wants a Roth component or a loan feature.

The three most common errors

• •Using last year's limits. For 2026 the numbers are $72,000 and $24,500. Filing a 2026 return on last year's limits leaves money on the table or, worse, leads to an excess contribution if a catch-up was mis-sized.
• •Applying 25 percent to gross Schedule C. The 25 percent rate belongs to W-2 compensation from an S corporation or C corporation. For Schedule C income, apply about 20 percent to net earnings after the half-SE-tax adjustment.
• •Missing the deferral election deadline. The employee deferral must be elected in writing by December 31 of the plan year, even though the money can be deposited up to the tax filing deadline including extensions. The employer contribution can be both decided and deposited by the extended deadline. Adopting the plan itself can be done up to the extended deadline for the employer portion only.

Roth deferrals and the Saver's Match interaction

The deferral side of a Solo 401(k) can be Roth. For a high earner, that is often the only way into Roth treatment at scale, because Roth IRA eligibility phases out at higher incomes while a Roth 401(k) deferral has no income limit.

One nuance for household members with lower income: starting January 1, 2027, the federal Saver's Match pays up to $1,000 into a retirement account for savers under the MAGI phase-outs ($20,500 to $35,500 single, $30,750 to $53,250 head of household, $41,000 to $71,000 joint). Roth contributions count toward earning the match, but the Treasury's payment must land in a non-Roth IRA. Gigaverse explains the mechanics on its Saver's Match Roth rule page.

What the shelter is worth over time

Illustrative only, using 6% annual growth, the rate the Treasury uses in its own Saver's Match projections, and not a prediction: the $60,000 earner contributing $35,650 a year for twenty years accumulates roughly $1.3 million before tax. The $150,000 earner contributing $52,400 reaches roughly $1.9 million. The difference between those figures and the roughly $276,000 a $7,500-a-year Roth IRA would produce over the same period is the entire case for adopting a plan. Investment returns are not guaranteed, and actual results will differ.

Gigaverse's free contribution tools run these numbers from your own Schedule C estimate, including the SE-tax adjustment and the age-50 catch-up.

Where Gigaverse fits

Gigaverse is a subscription retirement app built for people with 1099 income. Today it offers a Roth IRA through a FINRA/SIPC-member broker-dealer. Applications for a Solo 401(k) and a SEP IRA are open at gigaverse.ai/solo-401k and gigaverse.ai/sep-ira: you apply, a person confirms your eligibility and sends your plan documents, then you fund before the deadline. It also computes your limits, tracks contributions across every account you hold, and packages the numbers for your CPA. Gigaverse is pursuing SEC RIA registration, does not guarantee investment returns, and is paid by subscription rather than on assets, as explained on the how we make money page. The full high-earner breakdown lives on the Solo 401(k) for high earners page.