Freelancers, consultants, and small-business owners now have two of the most powerful retirement tools available anywhere in the tax code — the SEP IRA and the Solo 401(k). Both let self-employed savers push tens of thousands of dollars a year into tax-advantaged accounts. But the 2026 contribution limits, catch-up rules, and Roth features have widened the gap between them enough that the choice matters more than it did even a year ago.
The Headline Numbers for 2026
The IRS raised the overall defined contribution ceiling to $72,000 for 2026, up from $70,000 in 2025. That figure caps the combined employee and employer contributions any single participant can receive across a workplace plan.
For a SEP IRA, that entire $72,000 must come from the employer side. Contributions are limited to 25% of eligible compensation for W-2 employees, or roughly 20% of net self-employment earnings for sole proprietors after accounting for the deductible half of self-employment tax.
A Solo 401(k) reaches a similar ceiling through two channels. As the "employee" of your own business, you can defer up to $24,500 of compensation in 2026 — the same limit that applies to any traditional 401(k). Then, wearing your employer hat, you can add a profit-sharing contribution of up to 25% of compensation (or ~20% of net self-employment income) on top, up to that combined $72,000 cap.
Why the Solo 401(k) Often Wins at Middle Incomes
The math favors the Solo 401(k) whenever your self-employment income is modest. Because the employee deferral is a flat-dollar contribution — not a percentage of earnings — a Solo 401(k) lets you save meaningfully more when profits are lower.
Consider a freelance designer with $60,000 in net self-employment income. A SEP IRA would allow roughly $12,000 in contributions (20% of net earnings after the SE tax adjustment). A Solo 401(k) would allow the same $12,000 profit-sharing piece plus the full $24,500 employee deferral — a combined contribution north of $36,000. That gap only narrows at higher income levels where the 25% employer piece alone can hit the $72,000 cap.
Catch-Up and Roth Advantages
Solo 401(k) plans also unlock features SEP IRAs simply do not offer. Savers age 50 and older can add an $8,000 catch-up in 2026, and those ages 60–63 qualify for the SECURE 2.0 "super catch-up" of $11,250. Many Solo 401(k) providers now support Roth employee deferrals as well, giving self-employed savers a way to build tax-free retirement dollars alongside their pre-tax bucket.
SEP IRAs remain a pre-tax-only vehicle, with no catch-up contributions available. For a solo consultant in their early 60s trying to maximize savings in the final stretch before retirement, that difference alone can be worth tens of thousands of dollars.
When a SEP IRA Still Makes Sense
The SEP IRA's advantage is simplicity. There is no annual Form 5500 filing requirement until plan assets exceed $250,000, no plan document to maintain, and setup takes minutes at most custodians. For a sole proprietor with high, steady income who wants to make a large contribution once a year and move on, the SEP IRA remains a legitimate choice.
It is also easier to open late in the tax year — SEP IRAs can be established and funded as late as the extended tax filing deadline, while Solo 401(k) plans generally need to be established by December 31.
Practical Takeaways
- If your net self-employment income is under about $200,000, a Solo 401(k) will almost always let you save more.
- If you want Roth flexibility or catch-up contributions, only the Solo 401(k) offers them.
- If you have employees other than a spouse, neither plan works cleanly — a SEP IRA would require equal-percentage contributions for everyone, and a Solo 401(k) is limited to owner-only businesses.
- Confirm your custodian's cutoff dates. Missing a December 31 setup deadline for a Solo 401(k) can push you back to a SEP IRA for that tax year by default.
Sources: IRS Newsroom, Fidelity, Kiplinger, IRA Financial, Charles Schwab