Working for yourself comes with a lot of freedom and one big gap: nobody hands you a retirement plan. You set one up on your own, and the two names that come up most are the SEP IRA and the Solo 401(k). Both let you put away far more than a regular IRA, and both cut your tax bill. The right pick comes down to how much you earn and how much you want to save. Let’s break down how they stack up for 2026.
The Quick Version of Each Plan
Before the numbers, here is what each one is in plain terms.
SEP IRA
A SEP IRA is the low-effort option. You open it, you fund it, and there is almost no paperwork after that. Contributions come from the business side only, so you put in a percentage of your earnings and that money lowers your taxable income for the year.
Solo 401(k)
A Solo 401(k) is built for one-person businesses, or a business owner plus a spouse. It works in two parts. You contribute as the employee, and then your business contributes on top as the employer. That two-part setup is what lets you save more on the same income.
The 2026 Numbers Side by Side
This is where the real difference shows up.
SEP IRA limits for 2026
For 2026, you can put up to $72,000 into a SEP IRA. The catch is the cap: your contribution cannot go past 25% of your compensation. For someone self-employed, that works out to roughly 20% of net earnings after the self-employment tax adjustment. So to hit the full $72,000, you need a high income. There are no catch-up contributions in a SEP IRA, so age does not change your limit.
Solo 401(k) limits for 2026
A Solo 401(k) for 2026 lets you defer up to $24,500 as the employee. On top of that, your business can add a profit-sharing contribution of up to 25% of compensation. The combined total caps at $72,000 for people under 50. If you are 50 or older, an $8,000 catch-up pushes your ceiling to $80,000. And if you are between 60 and 63, the catch-up jumps to $11,250 for 2026, raising your total even higher.
Why the Solo 401(k) Usually Wins at Lower Incomes
Here is the part that decides it for most people. That $24,500 employee deferral does not depend on a percentage of your income. You can put it in regardless of how the profit math shakes out, as long as you earned at least that much.
Picture a freelancer who nets $80,000. With a SEP IRA, the contribution caps near 20% of net, which lands around $16,000. With a Solo 401(k), that same person puts in the full $24,500 employee deferral first, then adds a profit-sharing piece on top. The Solo 401(k) drops thousands more into the account on the exact same income. At moderate earnings, that gap is the whole story.
When the SEP IRA Still Makes Sense
The Solo 401(k) does not win every time. The SEP IRA has its own strong points.
You want zero hassle
A SEP IRA takes minutes to open and asks nothing of you at tax time beyond the contribution itself. A Solo 401(k) has more rules, and once the account balance passes $250,000 you file a short annual form with the IRS. For someone who wants to fund an account and forget it, the SEP IRA is the easier ride.
You have employees
A SEP IRA is a one-person tool in spirit, but the rules force you to contribute the same percentage for any eligible employee that you give yourself. A true Solo 401(k) only works if it is just you, or you and a spouse. The moment you hire a full-time employee, the Solo 401(k) no longer fits.
Your income is very high
At the top end, both plans reach the $72,000 cap, so the Solo 401(k) edge shrinks once your income gets large enough to max the SEP IRA on the percentage alone.
A Few Other Points Worth Knowing
Both plans share some ground that makes the choice easier.
Roth options
Many Solo 401(k) plans now offer a Roth side, so you pay tax now and pull the money out tax-free later. SEP IRAs run pre-tax in most cases, so if Roth savings appeal to you, that tilts things toward the Solo 401(k).
Deadlines
A SEP IRA can be opened and funded right up to your tax filing deadline, including extensions, which gives you room to decide after the year ends. A Solo 401(k) usually has to be opened by December 31 of the tax year, even though funding can come later. That timing rule trips people up, so mark it down.
How to Pick
If you run a one-person shop and earn a moderate income, the Solo 401(k) almost always lets you save more, and the Roth feature is a nice bonus. If you want the simplest account going, you have employees, or your income already maxes either plan on the percentage, the SEP IRA holds up well.
Run your real income through both before you open anything. The few minutes it takes to compare the contribution math can mean thousands more in your account and a smaller tax bill for the year.
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