SEP-IRA vs Solo 401(k): Retirement for the Self-Employed (2026 Limits)

Why the self-employed need their own plan

When you leave (or never had) a W-2 job, you lose more than the steady paycheck. You lose the retirement infrastructure that comes with it: the automatic payroll deduction, the plan someone else administers, and above all the employer match. No client is going to match your contributions. If money is going into a retirement account, you are the only one putting it there.

The IRS’s answer is to let self-employed people wear both hats. In a SEP-IRA or Solo 401(k), you act as the employer (and in the Solo 401(k), as the employee too), which unlocks contribution limits far beyond what a regular IRA allows. A regular IRA caps out at $7,500 for 2026 ($1,100 more if you’re 50 or older). The plans below can shelter many times that, with every dollar reducing your taxable income today.

Both plans key off the same input: your net self-employment income, the profit line from Schedule C. If you don’t know that number yet, the self-employment tax calculator will get you there.

The 2026 numbers

All figures below come from the IRS 2026 limit announcement (Notice 2025-67):

• Solo 401(k) employee deferral: $24,500. Catch-up for age 50 and older: $8,000. Special catch-up for ages 60 through 63: $11,250.
• Total defined-contribution limit (employee plus employer money combined): $72,000, plus catch-ups.
• SEP-IRA: the lesser of 25% of compensation or $72,000, with compensation capped at $360,000 for the calculation.
• Traditional/Roth IRA (for reference): $7,500, with a $1,100 catch-up at 50 and older.

One translation note that trips up nearly everyone: for the self-employed, the SEP’s “25% of compensation” works out to roughly 20% of net self-employment income after the deductible half of SE tax comes off. The same formula governs the employer side of a Solo 401(k). When you see both numbers quoted, they describe the same rule from two angles, not two different limits.

The structural difference that decides it

Strip away the branding and the two plans differ in exactly one load-bearing way:

• A SEP-IRA is employer-side only.Your business contributes roughly 20% of your net self-employment income on your behalf, and that’s the whole plan. No employee deferral exists.
• A Solo 401(k) is both sides. You get the same roughly-20% employer contribution, plusan employee deferral of up to $24,500 on top, because you’re the employee too.

That extra deferral layer is why the Solo 401(k) dominates at low and moderate incomes. When your profit is modest, 20% of it is a modest number, and the SEP is stuck there. The Solo 401(k) starts from the same 20% and stacks up to $24,500 of deferral on top of it. Only at high incomes, where the percentage formula alone approaches the shared $72,000 overall cap, do the two plans converge.

What that looks like at a moderate income

Picture a freelancer clearing a solid but not spectacular profit for the year. The employer-side math is identical under either plan: roughly a fifth of net earnings, after the SE-tax deduction shaves the base slightly. Under a SEP, that fifth is the ceiling. Done.

The same freelancer with a Solo 401(k) gets that identical employer piece and can then defer up to $24,500 of their own earnings as the employee. At a moderate income the deferral is usually the larger of the two pieces, which means the Solo 401(k) can roughly double or triple the total going into the account compared with a SEP. Add the $8,000 catch-up at 50 (or $11,250 at ages 60 through 63) and the gap widens further, since the SEP has no catch-up at all.

The pattern to remember: the lower your self-employment income, the more lopsided the comparison gets in the Solo 401(k)’s favor. If you’re still deciding what to charge so that retirement savings actually fit in your rates, the freelance rate calculator is built for exactly that planning question.

Eligibility: who can use which plan

Solo 401(k):owner-only businesses. Sole proprietors, single-member LLCs, and similar setups with no employees qualify, with one family-friendly exception: a spouse who works in the business can participate too. Hire a non-spouse employee who meets the eligibility rules and the “solo” part stops being true.

SEP-IRA: open to businesses with or without employees, but with a string attached. If you have eligible employees, you must cover them equally: whatever percentage of compensation you contribute for yourself, you contribute for them as well. For a true solo operator that clause never bites. For anyone planning to hire, it turns the SEP into a real cost commitment worth pricing out in advance.

The practical sorting rule: if you are (and intend to stay) a one-person shop, both doors are open and the comparison comes down to contribution room and admin tolerance. If employees are on the horizon, the SEP is the one that survives the transition, equal coverage and all.

Setup and deadlines

The SEP-IRA is the minimal-effort option: a short form, an account at almost any brokerage, and you’re running. There is no ongoing plan administration to speak of, which is why accountants reach for it when a client shows up late in the season wanting a deduction.

The Solo 401(k) asks a little more of you. It requires a formal plan document, providers differ in what paperwork they handle for you, and larger account balances can bring annual filing obligations. None of it is hard, but it is more than the SEP.

Deadlines are the detail to verify with your provider rather than assume: the rules differ by plan type, and they treat the act of establishing the plan and the act of funding it differently. Employee deferrals and employer contributions can also run on different clocks. The safe habit is to decide on your plan well before year-end rather than during filing season, so no option has already closed by the time you want to use it.

What these plans do (and don’t do) to your taxes

Pre-tax contributions to either plan reduce your income tax: the contribution comes off your income before the brackets apply, so the savings land at your marginal rate.

Neither plan reduces your self-employment tax. SE tax (15.3%, applied to 92.35% of net self-employment earnings) is calculated on your business profit before retirement contributions enter the picture. A maxed-out Solo 401(k) leaves your Schedule SE bill exactly where it was. Budget for both layers separately; our quarterly tax guide covers how to fold retirement contributions into your estimated payment math. And since retirement contributions interact with other income-tax breaks, it’s worth knowing how the QBI deduction fits alongside them.

Common mistakes when choosing

• Reading “25% of compensation” as 25% of your profit. For the self-employed, the formula lands at roughly 20% of net earnings after the SE-tax deduction. Sellers who budget for the bigger number find out at filing time that their allowed contribution is smaller than planned.
• Expecting a smaller SE tax bill. Contributions reduce income tax only. If your quarterly estimates assumed the retirement contribution would shrink the 15.3% layer, your estimates are short.
• Choosing a SEP for the simplicity, then wishing for the room.If you open a SEP and later want to save more than the percentage formula allows, the deferral you skipped doesn’t carry forward. Contribution room is use-it-or-lose-it by year.
• Opening a Solo 401(k) right before hiring. The plan stops fitting the moment a non-spouse employee becomes eligible. If a hire is realistically coming, think one plan ahead.
• Forgetting the IRA bucket entirely. The $7,500 IRA limit (plus the $1,100 catch-up at 50) sits alongside either plan. Savers who max a workplace-style plan and stop there leave tax-advantaged space on the table.

So which one should you pick?

• Pick the Solo 401(k)if you’re a one-person business (spouse optional) and you want to save more than roughly 20% of your profit. At low and moderate incomes it’s the only plan of the two that can get serious money into the account, and the catch-up provisions extend the lead for savers 50 and up.
• Pick the SEP-IRA if you value dead-simple setup over maximum room, if your income is high enough that the percentage formula alone hits your savings target, or if you have (or will soon have) employees the plan must cover.

Either way, the worst choice is the default one: no plan, with profit sitting in a checking account and a full income tax bill on all of it. Both of these accounts exist precisely because nobody else is funding your retirement now. The percentage you pick matters less than starting.

This guide is general information, not personalized tax advice. Plan rules, contribution formulas, and deadlines have edge cases (multiple businesses, S-Corp wages, controlled groups, employees nearing eligibility), and a CPA or plan provider should confirm your specific numbers. The figures here are sourced from IRS publications and current at 2026-06-10; limits change annually.