What Is a Solo 401(k)? A Guide for Freelancers and the Self-Employed
A Solo 401(k) is a retirement account built for one specific situation: you run your own business or freelance full-time, and you have no employees other than possibly a spouse. It works like a regular employer 401(k), except you’re on both sides of the desk — you get to contribute as the “employee” and again as the “employer,” which is exactly why it can shelter far more money than a standard IRA or even a SEP IRA at the same income.
Who actually qualifies
You need two things: self-employment income (1099 freelance work, consulting, or a sole proprietorship/single-member LLC) and no full-time employees besides a spouse who works for the business. You can still qualify with a day job on the side — plenty of people hold a W-2 job with an employer 401(k) while also running a freelance business that opens its own Solo 401(k) for the 1099 income. The moment you hire a non-spouse employee who works 1,000+ hours in a year, you generally have to stop contributing new money to the Solo 401(k) and convert to a plan that covers employees, like a SEP IRA or a standard 401(k).
How the two-part contribution actually works
This is the part that makes the Solo 401(k) worth understanding in detail, because most freelancers underestimate how much it lets them shelter.
Part 1 — Employee deferral. As the “employee,” you can defer up to $24,500 of your income in 2026, either pre-tax or as a Roth contribution, regardless of your net profit (as long as you earned at least that much). If you’re 50 or older, an additional $7,500 catch-up brings your personal deferral to $32,000.
Part 2 — Employer contribution. As the “employer,” your business can also contribute up to 25% of your net self-employment income (net profit minus half your self-employment tax).
Combined limit. These two pieces stack, up to a total of $72,000 for 2026 ($79,500 with the standard 50+ catch-up).
Here’s what that looks like on real income, assuming a full $24,500 employee deferral each time:
| Net SE income | Employer contribution (25%) | Employee deferral | Total Solo 401(k) contribution |
|---|---|---|---|
| $50,000 | ~$11,570 | $24,500 | ~$36,070 |
| $100,000 | ~$23,140 | $24,500 | ~$47,640 |
| $175,000 | ~$40,500 | $24,500 | ~$65,000 |
| $290,000+ | $72,000 (capped) | included in cap | $72,000 |
A freelancer netting $100,000 can shelter nearly half their income from current-year taxes — something no IRA, and no SEP IRA on its own, can match.
Solo 401(k) vs. SEP IRA: why the 401(k) usually wins
Both accounts let you contribute the same 25%-of-income employer piece. The difference is the Solo 401(k) adds the $24,500 employee deferral on top of that, while a SEP IRA stops at the employer contribution alone. For a full side-by-side, including the Roth option and loan provisions the SEP IRA doesn’t have, see our SEP IRA vs. Solo 401(k) comparison. The short version: unless you’re planning to hire employees soon or want the absolute lowest-maintenance account, the Solo 401(k) shelters more money at almost every income level.
Traditional vs. Roth: which half should be Roth
Most major providers now let you choose Roth (after-tax) treatment on the employee deferral portion — the employer contribution is generally required to stay pre-tax. If you’re early in your career or expect to be in a higher tax bracket in retirement than you are now, running your $24,500 employee deferral through the Roth option means that money (and all its growth) comes out completely tax-free later. If you’re in your peak earning years and want the deduction now, keep the employee deferral pre-tax like the employer piece.
Where to open one, and what it actually costs
Fidelity, Charles Schwab, and E*TRADE all offer no-fee, no-minimum Solo 401(k) plans, which is enough for most freelancers who just want low-cost index funds and a straightforward pre-tax deferral. Specialized Solo 401(k) providers charge roughly $250-600 a year but unlock features the free brokerage plans usually skip: Roth employee deferrals, participant loans (borrow up to 50% of your balance, capped at $50,000), and self-directed investing into real estate or private assets. Most freelancers who just want to invest in a normal mix of index funds don’t need to pay for the upgrade.
One deadline matters more than any other: the plan itself must be opened by December 31 of the tax year you want to contribute for, even though the actual contribution deposit deadline extends to your tax filing date (plus extensions). Waiting until tax season to open the account for last year is the single most common way freelancers miss out on a full year of contributions.
How this fits with the rest of your finances
A Solo 401(k) is a powerful tool, but it isn’t the first move. Before maxing one out:
- Pay off high-interest debt — credit cards above 10% APR cost more than almost any realistic investment return.
- Build a cash cushion. An HSA can double as a stealth retirement account once your emergency fund is solid, but liquid savings should come first.
- Budget for the irregular income that comes with freelancing — zero-based budgeting works well here because it forces you to plan contributions around cash flow that isn’t the same every month.
Once contributions are automated, the last decision is what to actually invest in — the index funds for beginners guide covers how to build a simple, low-cost portfolio inside the account.
The bottom line
A Solo 401(k) lets a freelancer or self-employed person contribute as both employee and employer, sheltering up to $72,000 in 2026 — often tens of thousands more than a SEP IRA at the same income. It costs nothing to open at most major brokerages, but the plan has to exist by December 31 to count for that tax year, so this isn’t a task to leave until you’re filing your return.
