SEP IRA vs Solo 401(k): Which One Lets You Save More?

When you work for yourself, nobody hands you a 401(k), so building a retirement plan is on you. The upside is that the self-employed options are generous, often more generous than what employees get, and they cut your tax bill in the year you contribute. The two most popular are the SEP IRA and the Solo 401(k), and while they sound similar, they reach their limits in very different ways.

The SEP IRA

A SEP IRA is the simple one. You contribute as the employer, up to roughly 20 percent of your net self-employment earnings, capped at 72,000 dollars for 2026. There are no employee contributions, no catch-up for being older, and not much paperwork. The trade-off is that if you have employees, you generally have to contribute the same percentage for them as you do for yourself, which gets expensive fast.

The Solo 401(k)

A Solo 401(k) is for the self-employed with no employees other than a spouse, and its trick is that you wear two hats. You contribute as the employee, up to 24,500 dollars for 2026, and then again as the employer with a profit-sharing piece. Together those can reach the same overall cap, but because of the employee contribution you get there at a much lower income than a SEP would allow. If you are 50 or older you can add a catch-up contribution, and there is an even larger one in your early sixties.

Why the Solo 401(k) usually wins for savers

Say you net 60,000 dollars from your business. A SEP would cap your contribution at around 20 percent of that. A Solo 401(k) lets you put in a big chunk as the employee first, then add the employer piece on top, so you can shelter far more of that 60,000. The Solo 401(k) also allows Roth contributions and even loans, which a SEP does not. That is why higher savers at modest incomes tend to prefer it.

Deadlines and paperwork

A SEP is easy on timing: you can open and fund it right up to your tax filing deadline, including extensions. A Solo 401(k) can also be adopted by your filing deadline for the employer contribution under current rules, but the employee deferral piece has tighter timing for a brand new plan, so it is smart to set one up before year-end if you want to max it. The Solo 401(k) does add a little paperwork once its assets cross 250,000 dollars.

Every dollar figure here is for 2026 and changes most years, so confirm the current limits before you contribute.

How Vuuv helps

How much you can contribute depends on your net self-employment earnings, which means it depends on clean books. Vuuv keeps your income and expenses organized all year so that figure is ready when you are deciding how much to stash. Pair this with our guides to self-employment tax and how much to set aside for taxes and you will have the full picture of what your business income can do.

This article is general information, not tax advice. Tax rules change and every situation is different. Confirm the details against current IRS guidance or talk to a qualified tax professional before you file.