Retirement contributions do double duty for freelancers: they’re the one deduction that’s also actually yours to keep, not just money that stops being taxed this year. Most freelancers either skip this entirely or default to whichever account their bank pushes hardest — usually without knowing there’s a real, sometimes dramatic difference between the two main options at their actual income level.
In This Guide
Go Deeper
Five topics on this page have a full breakdown of their own:
How Much Should You Actually Save?
A CPA’s framework for irregular freelance income, built around your worst month, not your average.
Backdoor Roth IRA
For high-income freelancers locked out of direct Roth contributions — the mechanics, the pro-rata trap, and the 2026 thresholds.
Traditional vs. Roth Solo 401(k)
Which to choose, plus the sole-proprietor exemption from the 2026 Roth catch-up mandate.
If You Stop Freelancing
What happens to your Solo 401(k), and the Form 5500-EZ penalty most people never hear about until it’s too late.
SIMPLE IRA for Freelancers
The honest answer on the third option — and when it actually beats a SEP IRA or Solo 401(k).
SEP IRA vs. Solo 401(k): The Core Difference
SEP IRA — employer contributions only, up to 25% of compensation (roughly 20% after the self-employment earned-income adjustment for sole proprietors). No employee deferral option. Simple to set up, minimal paperwork, no annual filing requirement.
Solo 401(k) — you contribute in two roles at once: as the “employee,” deferring up to $24,500 of your own compensation (2026), and as the “employer,” adding a profit-sharing contribution of up to 25% of compensation. Because you’re filling both roles, you reach meaningful contribution levels at much lower income than a SEP IRA allows. Once you’ve picked this account, there’s a further choice inside it — full breakdown of Traditional vs. Roth in the card above.
The practical difference is large at lower income levels. A sole proprietor netting $60,000 can contribute roughly $12,000 to a SEP IRA (25%-ish of net earnings) — but up to $36,000 to a Solo 401(k), because the $24,500 employee deferral doesn’t depend on the 25% employer-side math at all. There’s also a third option worth knowing about — a SIMPLE IRA — covered in the card above, though it rarely beats either of these for a true solo freelancer.
The Crossover Point
This gap closes as income rises. Once net self-employment income crosses roughly $175,000, both accounts allow similar total contributions, since the SEP IRA’s 25%-of-compensation ceiling eventually catches up to what the Solo 401(k)’s combined employee-plus-employer structure produces. Below that threshold, the Solo 401(k) is almost always the more generous choice. Above it, a SEP IRA’s simpler administration and lower paperwork burden can make it the more practical one, even if the dollar difference is small.
2026 Contribution Limits
| Under 50 | Age 50–59 | Age 60–63 | |
| Combined annual limit | $72,000 | $80,000 | $83,250 |
| Employee deferral (Solo 401(k) only) | $24,500 | $32,500 | $35,750 |
The combined limit is the same ceiling for both SEP IRA and Solo 401(k) — the difference is how you get there, not how high you can go. Catch-up contributions sit on top of the base limit rather than inside it, which is why the 50+ totals are higher than the standard cap plus the deferral alone would suggest.
A New Rule for 2026: The Roth Catch-Up Requirement
This is genuinely new and worth knowing before you assume your catch-up contribution works the way it used to: starting January 1, 2026, anyone age 50+ who earned over $150,000 in prior-year FICA W-2 wages is required to make their catch-up contributions as Roth — after-tax, not pre-tax — under SECURE 2.0. If your Solo 401(k) plan doesn’t support Roth contributions, this can block you from making catch-up contributions at all until the plan is amended to allow them.
The detail worth knowing if you’re weighing an S-corp election: that $150,000 trigger is based specifically on FICA W-2 wages. A sole proprietor or unincorporated single-member LLC has no W-2 wages at all — that income runs through Schedule C and self-employment tax instead, which means an unincorporated freelancer, even one earning well past $150,000, technically falls outside this mandate and retains full access to pre-tax catch-up contributions. An S-corp owner paying themselves a W-2 salary above that threshold does not have that option. This is a real factor worth weighing alongside the SE tax math in the LLC vs. S-Corp guide, not a separate, unrelated consideration. Full breakdown of this exemption in the card above.
If you’re 50 or older and relying on the catch-up amount as part of your plan, confirm your plan document actually supports Roth contributions before assuming that room is available to you in 2026. This same 2026 shift toward Roth treatment shows up again in the backdoor Roth breakdown in the card above.
Deadlines That Actually Matter
- Solo 401(k) plan adoption: under SECURE 2.0, a Solo 401(k) can now be adopted as late as your tax filing deadline, including extensions — the old hard December 31 plan-establishment deadline was extended, for the employer profit-sharing portion specifically
- Employee deferral election: the plan still needs to be active before year-end if you want to make an employee deferral for that same tax year — you can’t defer salary you’ve already received, so this part of the old December 31 pressure still applies in practice
- Employer-side contributions (both account types): can be made up until your business tax filing deadline, including extensions
In practice: if you’re only funding the employer profit-sharing side, or you’re deciding late in the year with limited income visibility, a Solo 401(k) is no longer automatically ruled out the way it once was. If you specifically want to make an employee deferral for the year, the plan still needs to exist before December 31.
How This Connects to an S-Corp Election
If you’ve elected S-corp status, your contribution base for either account is limited to your W-2 salary — not your net business profit, and not your distributions. This is the same trade-off covered in the LLC vs. S-Corp guide: minimizing your salary to maximize SE tax savings also shrinks the compensation base your retirement contributions are calculated against. The two decisions aren’t independent — running them together, rather than optimizing salary in isolation, is what actually protects both numbers.
Worked Example
A freelancer nets $90,000 in 2026, under 50, taxed as a default LLC (no S-corp election).
SEP IRA: roughly 20% of net self-employment earnings after the SE tax deduction — approximately $16,700.
Solo 401(k): $24,500 employee deferral, plus an employer contribution of roughly 20% of the same adjusted net earnings (~$16,700 — calculated as net profit minus half of your self-employment tax) — a combined total around $41,200, well under the $72,000 overall cap but nearly two and a half times the SEP IRA amount at this exact income level.
This is the crossover-point math in action: at $90,000, still well below the ~$175,000 convergence zone, the Solo 401(k)’s dual-contribution structure produces a materially larger deduction for the same income.
Getting Started
- Compare your actual numbers at your income level — don’t assume one account is better without running both
- If you want to make an employee deferral this year, open the Solo 401(k) well before December 31 — the employer-side extension doesn’t cover this part
- Confirm your plan supports Roth contributions if you’re 50+ and plan to use the catch-up amount
- Set the employee deferral election in writing before December 31, even if you fund it later
- Keep contribution confirmations and plan documents on file, same as any other deduction
Sources: IRS Notice 2025-67 (2026 retirement plan cost-of-living adjustments); IRC §415(c)(1)(A) (defined contribution annual additions limit); IRC §402(g)(1) (elective deferral limit); SECURE 2.0 Act provisions on Roth catch-up contributions effective 2026 and the extended Solo 401(k) plan-adoption deadline; Solo 401(k) and SEP IRA establishment and contribution deadline rules.
This article is educational content, not individualized tax or legal advice. Consult a qualified professional about your specific situation.