Self-employed workers and small business owners have access to retirement accounts that offer some of the highest contribution limits in the tax code. A SEP IRA and a Solo 401(k) are both excellent options — but they work differently, and the better choice depends on your income level, whether you have employees, and how much paperwork you want to deal with. Here is how to decide between them.
SEP IRA: The Basics
A SEP (Simplified Employee Pension) IRA is one of the simplest retirement accounts available to self-employed workers and small business owners. Setup takes about 15 minutes at any major brokerage. There are no annual IRS filing requirements.
Contribution limit (2026): Up to 25% of net self-employment income, capped at $70,000 (2026 limit, subject to IRS adjustment).
How the contribution is calculated: For self-employed individuals, the effective contribution rate is approximately 20% of net self-employment income (after the deduction for half of self-employment tax). On $100,000 net profit, you can contribute roughly $18,587.
Deadline: Contributions can be made up to the tax filing deadline, including extensions (October 15 for sole proprietors).
Investment options: Any IRA-eligible investment — stocks, bonds, ETFs, mutual funds, CDs.
Employees: If you have W-2 employees who meet eligibility requirements, you must contribute the same percentage to their SEP IRAs as you contribute to your own. This makes SEP IRAs expensive if you have employees.
Solo 401(k): The Basics
A Solo 401(k) — also called an Individual 401(k) or Self-Employed 401(k) — is a 401(k) plan for business owners with no full-time employees other than themselves and a spouse. It allows contributions in two separate buckets: employee elective deferrals and employer profit-sharing contributions.
Contribution limit (2026): Up to $70,000 total (or $77,500 if 50 or older, with $7,500 catch-up).
Employee deferral: Up to $23,500 in 2026 (the standard 401(k) limit), regardless of your business income. If you earn $50,000, you can still contribute $23,500 as an employee deferral.
Employer contribution: An additional 25% of net self-employment income (up to the overall limit).
Roth option: Most Solo 401(k) providers allow Roth contributions, meaning you can make after-tax employee deferrals that grow and are withdrawn tax-free in retirement.
Loan provision: Many Solo 401(k) plans allow loans of up to 50% of the account balance or $50,000, whichever is less.
Deadline: The plan must be established by December 31 of the tax year you want contributions to apply to. Contributions can be made until the tax filing deadline.
Employees: Available only to businesses with no full-time employees other than the owner and spouse. The moment you hire a W-2 employee who works 1,000+ hours per year, you can no longer contribute to a Solo 401(k).
Annual filing: Once the account balance exceeds $250,000, you must file Form 5500-EZ annually with the IRS.
SEP IRA vs. Solo 401(k): Side-by-Side Comparison
| Feature | SEP IRA | Solo 401(k) |
|---|---|---|
| 2026 contribution limit | $70,000 (25% of comp) | $70,000 ($77,500 with catch-up) |
| Best for lower incomes | No | Yes (employee deferral doesn’t depend on income) |
| Roth option | No | Yes |
| Loan provision | No | Yes (many providers) |
| Setup complexity | Very simple | Moderate |
| Annual IRS filing | None | Form 5500-EZ if balance over $250K |
| Employees allowed | Yes (but expensive) | No (owner + spouse only) |
| Plan establishment deadline | Tax filing deadline | December 31 of tax year |
When Solo 401(k) Wins
The Solo 401(k) is usually the better choice for most self-employed workers because it allows larger contributions at lower income levels. If you earn $60,000 in net self-employment income, you can contribute $23,500 in employee deferrals plus roughly $10,800 in employer contributions — a total of approximately $34,300. A SEP IRA on the same income would cap contributions at roughly $11,200.
The Solo 401(k) is also better if you want a Roth contribution option, want the ability to take a loan, or want to maximize your retirement savings while your income is still growing.
When SEP IRA Wins
The SEP IRA is better if you value simplicity above all else, if you have or plan to hire employees (before the employee count disqualifies you from Solo 401(k)), or if your income is high enough that the 25% employer contribution alone fills your desired savings amount. At very high income levels — above $200,000 in net self-employment income — both plans reach roughly the same contribution ceiling.
The SEP IRA also wins if you missed the December 31 plan establishment deadline for the current tax year — you can still open and fund a SEP IRA as late as October 15 of the following year.
Where to Open Each Account
SEP IRA: Fidelity, Vanguard, Schwab, and most major brokerages offer free SEP IRA setup with no account minimums.
Solo 401(k): Fidelity and Schwab offer free Solo 401(k) plans with no setup fees. Vanguard offers Solo 401(k) plans but has a simpler feature set (no Roth, no loans). Avoid providers that charge annual maintenance fees for this account type.
Bottom Line
For most self-employed workers, the Solo 401(k) is the better retirement account because it allows higher contributions at lower income levels and includes a Roth option. The SEP IRA is the right choice if you value simplicity, have employees, or missed the year-end plan establishment deadline. Open a Solo 401(k) at Fidelity or Schwab before December 31 to take advantage of this year’s contribution limits.