If you’re self-employed, you’ve probably heard that you should open a retirement account. You may have even gotten as far as narrowing it down to two options: the Solo 401(k) and the SEP IRA. And then you stalled — because everything you’ve read either oversimplifies the comparison or buries you in IRS jargon.
Here’s the good news: both of these plans are excellent. Either one puts you ahead of the majority of self-employed workers who have no retirement plan at all. But they’re built differently, and depending on your income, your tax situation, and how you run your business, one of them will almost certainly be a better fit.
Let’s break it down.
What Each Plan Actually Is
Both plans exist to let self-employed people do what W-2 employees take for granted: put money away for retirement with meaningful tax advantages. But they use different mechanics to get there.
SEP IRA (Simplified Employee Pension) is the simpler of the two. You contribute as the employer only — up to 25% of your net self-employment income, with a maximum of $72,000 for 2026. There’s one contribution bucket. You put money in, it grows tax-deferred, and you pay taxes when you take it out in retirement.
Solo 401(k) — sometimes called an Individual 401(k) — gives you two contribution buckets. You can contribute as the employee (up to $24,500 in 2026, the same limit as any 401(k) participant), and as the employer (up to 25% of net self-employment income on top of that). The combined ceiling is the same $72,000 — but you can reach it at a much lower income level.
The short version: a SEP IRA gives you one lever to pull. A Solo 401(k) gives you several — and at most income levels, that flexibility translates directly into larger contributions.
The Income Math
This is where the decision usually becomes clear. The Solo 401(k)‘s employee deferral is the key differentiator — and it matters most at moderate income levels.
Example: $80,000 in net self-employment income
With a SEP IRA, your maximum contribution is roughly $14,870 (the effective rate for sole proprietors is about 18.59% of gross self-employment income, after adjusting for the self-employment tax deduction — not a clean 25%).
With a Solo 401(k), you can contribute that same $14,870 as the employer, plus $24,500 as the employee. That’s roughly $39,370 — more than double what the SEP allows at the same income.
Example: $150,000 in net self-employment income
SEP IRA: approximately $27,865 (18.59% effective rate).
Solo 401(k): $24,500 as the employee, plus the same ~$27,865 as the employer. Total: approximately $52,365.
To max out a SEP IRA at $72,000, you’d need roughly $290,000 or more in net self-employment income. To max out a Solo 401(k) at $72,000, you need about $190,000 — because the $24,500 employee deferral does a lot of the work regardless of your income level.
At every income level below roughly $290,000, the Solo 401(k) lets you contribute more. That’s the crossover insight that most comparison articles bury in a footnote.
The Roth Advantage
SEP IRA contributions are pre-tax only. There is no Roth option. Every dollar you contribute will be taxed when you withdraw it in retirement.
The Solo 401(k) offers a Roth option on your employee deferrals. That means you can contribute after-tax dollars that grow and are withdrawn completely tax-free in retirement — provided you meet the holding requirements (age 59 1/2, and the account has been open at least five years).
Why does this matter? If you’re in the early or middle stages of your career and expect your income to grow, paying taxes on contributions now at a lower rate — and never paying taxes on the growth — can be worth significantly more over a 20- or 30-year horizon. For a 30-year-old freelancer whose income is climbing, the Roth option alone can be worth tens of thousands of dollars in retirement.
Some Solo 401(k) plans also allow what’s known as the mega backdoor Roth strategy — making after-tax employer contributions and converting them in-plan to Roth. This is an advanced move that isn’t available in every plan, but it can dramatically increase the amount of money you funnel into tax-free growth.
One note for 2026: SECURE 2.0 introduced a rule requiring that catch-up contributions for those earning over $150,000 in wages be made as Roth. This primarily affects people with W-2 income, but if you have both W-2 and self-employment income, it’s worth understanding.
Loans
Life doesn’t always cooperate with your savings plan. A Solo 401(k) can include a loan provision — letting you borrow up to $50,000 or 50% of your vested account balance, whichever is less. No credit check, no application process, no restrictions on how you use the funds. You repay the loan (with interest, typically pegged to the prime rate) back to your own account over five years.
A SEP IRA has no loan provision. If you need to access the money before age 59 1/2, your only option is an early withdrawal — which triggers income taxes plus a 10% penalty.
For freelancers and creators with variable income, the loan provision is a real safety valve. It’s not something you want to rely on, but knowing it exists can change how you think about liquidity.
Simplicity
This is where the SEP IRA earns its keep.
Setting up a SEP IRA is quick. You fill out IRS Form 5305-SEP (a two-page document), open the account at any major brokerage, and start contributing. There are no annual filing requirements with the IRS. No plan documents to maintain. No compliance testing.
A Solo 401(k) requires more setup. You’ll need a plan document — especially if you want the Roth option or loan provision, since those have to be specifically written into the plan. Many providers offer free or low-cost Solo 401(k) plans, but the setup takes more time and attention.
Once your Solo 401(k) assets exceed $250,000, you’re required to file IRS Form 5500-EZ annually. It’s not complicated, but it’s one more thing on the list — and for someone already juggling a business, it’s worth factoring in.
If you’re making $40,000 or $50,000 in self-employment income and just want the easiest possible way to start saving for retirement with a tax deduction, the SEP IRA’s simplicity is a legitimate advantage.
What Happens When You Hire
This is the constraint that catches people off guard.
A Solo 401(k) is only available if you have no common-law employees — with the exception of your spouse. The moment you hire someone who works 1,000 or more hours in a year, your Solo 401(k) is no longer eligible as a solo plan. You’d need to convert it to a standard 401(k) or transition to another plan type.
A SEP IRA can cover employees. But there’s a catch: you must contribute the same percentage of compensation for every eligible employee as you contribute for yourself. If you’re putting in 25% for yourself, you’re putting in 25% for everyone who qualifies. That gets expensive fast.
For most freelancers and creators, this is a non-issue. You’re working with contractors, not W-2 employees. But if you have any plans to build a team with actual employees in the next few years, think about this before you choose — because unwinding a Solo 401(k) mid-growth is an administrative headache you don’t need.
The Comparison
| SEP IRA | Solo 401(k) | |
|---|---|---|
| Max contribution (2026) | $72,000 | $72,000 (+ catch-up if 50+) |
| Income needed to max out | ~$290,000+ | ~$190,000+ |
| Roth option | No | Yes |
| Loans | No | Yes, if plan allows |
| Setup complexity | Low | Moderate |
| Annual IRS filing | None | Form 5500-EZ if assets > $250k |
| Employees allowed | Yes (must contribute equally) | No (spouse excepted) |
| Catch-up contributions (age 50+) | No | Yes ($8,000 in 2026) |
Which One Should You Pick?
The SEP IRA makes sense if you want the simplest possible setup, your self-employment income is modest, you don’t need the Roth option, or you might hire employees in the near future. It’s the “just get started” plan — and there’s nothing wrong with that.
The Solo 401(k) makes sense if you want to maximize your contributions at any income level, you value Roth flexibility, you want the option to take a loan against your balance, and you’re confident your business will stay a one-person (or one-couple) operation. For most self-employed people earning $60,000 or more, this is the stronger play.
Either way: the most important thing is to actually open something. The gap between a SEP IRA and a Solo 401(k) is real but manageable. The gap between having a retirement plan and not having one is enormous — and figuring out how much you actually need starts with having a place to put the money. Every year you delay costs you compounding — and compounding is the one advantage that no amount of future income can replace.
And if you pick one today and your situation changes later? You can switch. A SEP IRA can be replaced by a Solo 401(k). A Solo 401(k) can be rolled into an IRA. These aren’t permanent, irreversible decisions. They’re tools. Pick the one that fits now, and adjust as your business evolves.
Keep reading:
- Roth vs. Traditional IRA: A Decision Framework That Actually Works
- How Much Do I Need to Retire? (Why the Answer Isn’t a Number)
- What to Look for in a Financial Advisor (And the Red Flags Most People Miss)
This article is educational and not a substitute for personalized financial advice. Your income, tax situation, and goals are unique — work with a qualified advisor before making financial decisions.
Justin Moyer is the founder of KWM Financial LLC, a fee-only registered investment advisory firm. He works with content creators, freelancers, and anyone building wealth on their own terms.