Gig Finance Guide
SEP-IRA vs Solo 401(k) for Gig Workers
Two of the most powerful retirement accounts for the self-employed are the SEP-IRA and the Solo 401(k). Both let gig workers shelter far more than a regular IRA, but they differ on contribution limits, Roth options, paperwork, and deadlines. Here's a head-to-head to help you pick — and it pairs with our broader gig-worker retirement guide.
SEP-IRA
Simplest to open and fund; employer-style contribution only.
Solo 401(k)
Highest potential total; employee + employer contributions.
Roth option
Solo 401(k)s often allow Roth; SEP-IRAs traditionally don't.
Deadlines differ
A Solo 401(k) usually must be opened by year-end; SEP-IRAs are more flexible.
How the SEP-IRA works
A SEP-IRA is the simplest self-employed plan: most brokerages open one free in minutes, and contributions are a percentage of your net self-employment earnings up to an annual IRS cap, generally tax-deductible. There's only an 'employer' contribution — no separate employee deferral.
Its big advantages are simplicity and flexibility: you can vary or skip contributions year to year, and you can typically open and fund it up to your tax-filing deadline (including extensions). That makes it ideal if your income is unpredictable or you decide to contribute after year-end.
How the Solo 401(k) works
A Solo 401(k) (one-participant 401(k)) is for self-employed people with no employees. You contribute in two roles: as the 'employee' (an elective deferral up to the annual limit) and as the 'employer' (a profit-sharing percentage). Combining both usually allows a larger total contribution than a SEP-IRA at the same income — especially at low-to-moderate earnings.
Many providers also offer a Roth option on the employee portion, letting you lock in tax-free growth. The trade-offs: a bit more setup and paperwork, an annual filing once the balance is large, and a stricter deadline to establish the plan.
Head-to-head
Contributions: the Solo 401(k) usually wins, because the employee deferral lets you reach a high contribution at a lower income than a SEP-IRA's percentage-only formula. Simplicity: the SEP-IRA wins — less paperwork and no plan document. Roth: the Solo 401(k) typically offers it; the SEP-IRA traditionally doesn't.
Deadlines: SEP-IRAs are more forgiving (often fundable up to the extended filing deadline), while a Solo 401(k) generally must be established by December 31 to defer that year's income. Exact limits and deadlines change yearly — confirm them with the IRS or your provider.
How to choose
If you want maximum simplicity or you're deciding after year-end, the SEP-IRA is hard to beat. If you want to contribute the most possible (especially at moderate income), want a Roth option, and don't mind a little paperwork, the Solo 401(k) usually wins.
Note you generally can't max both at the same time on the same income, and having employees changes the picture. A tax professional or fee-only advisor can run the numbers for your situation. This is educational information, not investment advice.
Frequently asked questions
Is a SEP-IRA or Solo 401(k) better for gig workers?
It depends. A Solo 401(k) usually allows higher total contributions (employee + employer) and often a Roth option, making it great for higher savers who don't mind paperwork. A SEP-IRA is simpler, more flexible, and can be opened after year-end — ideal for unpredictable income. Confirm current limits with the IRS.
Can a gig worker contribute more to a Solo 401(k) than a SEP-IRA?
Often yes, especially at low-to-moderate income, because a Solo 401(k) adds an employee elective deferral on top of the employer profit-sharing contribution, while a SEP-IRA is employer-contribution only. At high income the gap narrows. Check the current year's IRS limits.
Does a SEP-IRA or Solo 401(k) have a Roth option?
Solo 401(k)s commonly offer a Roth option on the employee deferral, letting contributions grow tax-free. SEP-IRAs traditionally have not offered Roth treatment, though rules evolve — confirm what your provider supports and the current IRS guidance.
What are the deadlines to open each account?
A SEP-IRA can typically be opened and funded up to your tax-filing deadline (including extensions), while a Solo 401(k) generally must be established by December 31 to defer that year's income (funding can come later). Always confirm current deadlines with the IRS or your provider.
Can I have both a SEP-IRA and a Solo 401(k)?
You can have both accounts, but you generally can't max out both on the same self-employment income because of combined limits, and contributing to both adds complexity. Most gig workers pick one primary plan. A tax professional can help you optimize.
Authoritative resources
Helpful calculators
More gig finance guides
Run your whole gig business in one place
UnifyOne tracks your earnings, expenses, mileage, and tax set-aside across every platform — so taxes, budgeting, and planning all work from one set of numbers.
This is educational information, not financial, tax, or investment advice. Rules and dollar limits change yearly — confirm current details with the IRS, HealthCare.gov, or a qualified professional for your situation.