Solo 401(k) vs SEP-IRA for Gig Workers: Which Saves More Tax in 2026?
If you drive for DoorDash, freelance on Upwork, or run any 1099 side hustle, the two best retirement accounts for cutting your tax bill are the Solo 401(k) and the SEP-IRA. Both let a self-employed person shelter tens of thousands of dollars from federal, self-employment, and state tax — but they behave very differently at low-to-mid gig income. This guide breaks down 2026 contribution limits, real-world tax savings, and which one wins for a typical Dasher, Uber driver, or freelancer.
Why gig workers need a self-employed retirement plan
Every 1099 dollar you contribute to a Solo 401(k) or SEP-IRA reduces your adjusted gross income, which lowers federal income tax AND state income tax. Traditional IRA contributions never reduce self-employment tax, and neither do these — but the AGI reduction alone can save $2,000–$8,000 per year for gig workers earning $30k–$100k in net Schedule C profit.
Solo 401(k) 2026 contribution limits
You wear two hats: employee and employer. Employee deferral: up to $23,500 (or 100% of net earnings, whichever is less). Employer profit-sharing: up to 25% of net self-employment earnings. Total combined: $70,000 in 2026 ($77,500 if age 50+). This is the highest shelter available to any solo self-employed person.
SEP-IRA 2026 contribution limits
Employer contributions only — no employee side. You can contribute up to 25% of net self-employment earnings (effectively ~20% after the SE-tax adjustment), capped at $70,000. There's no age-50 catch-up.
The math at $40,000 net gig profit
Net Schedule C: $40,000. After half-SE deduction, net earnings from self-employment ≈ $36,900. SEP-IRA max: ~$7,300 (20% × $36,900). Solo 401(k) max: $23,500 employee deferral + $7,300 profit-share = $30,800. At a 22% marginal federal + 5% state = ~$8,300 tax saved with Solo 401(k) vs ~$1,970 with SEP-IRA. Solo 401(k) wins by a wide margin at this income.
The math at $150,000 net gig profit
Net earnings ≈ $138,400. SEP-IRA max: ~$27,700. Solo 401(k) max: $23,500 + $27,700 = $51,200. Solo 401(k) still wins, but the gap narrows because the employer side is identical.
The break-even point
SEP-IRA and Solo 401(k) put the same amount in the account only when your income is so high that the employer 25% contribution already hits the $70,000 cap (around $350,000 net SE earnings). Below that, the Solo 401(k)'s $23,500 employee deferral is free money the SEP-IRA cannot match.
Roth option
Solo 401(k)s can accept Roth employee deferrals (up to $23,500 in 2026) — no AGI limit and no need to backdoor. SEP-IRAs allow Roth contributions starting in 2026 under SECURE 2.0, but adoption is slow and few brokerages support it yet.
Setup and paperwork
SEP-IRA: 15-minute open at Fidelity/Schwab/Vanguard, no annual filing. Solo 401(k): slightly longer setup, requires Form 5500-EZ once plan assets exceed $250,000. Both are free at major brokerages.
Deadlines for 2026 tax year
SEP-IRA: contributions due by your tax filing deadline including extensions — October 15, 2027 if you file Form 4868. Solo 401(k): plan must be established by December 31, 2026; employee deferrals designated by year-end, employer contribution funded by the filing deadline plus extensions.
Which one to pick if you also have a W-2 with a 401(k)
The $23,500 employee-deferral limit is shared across all 401(k) plans you participate in — including your W-2 employer's. If you're already deferring $23,500 at work, the Solo 401(k) employee side is used up and only the employer profit-share is left. In that case a SEP-IRA is simpler and gets you the same result.
Backdoor Roth impact
Traditional SEP-IRA balances count toward the IRS pro-rata rule and can make backdoor Roth conversions expensive. Solo 401(k) balances are excluded from that calculation — a big reason high-income freelancers move SEP money into a Solo 401(k).
Loans and hardship access
Solo 401(k)s can permit participant loans up to 50% of balance or $50,000. SEP-IRAs never allow loans. If liquidity matters, Solo 401(k) wins.
How the contribution reduces your quarterly estimates
Every dollar you plan to contribute lowers your projected income tax, which lowers each Form 1040-ES payment. Estimate contributions in Q1 so your quarterlies aren't inflated. Use our [quarterly tax calculator](https://gigmytax.com/calculators/quarterly-tax) to model the change.
Worked example — full-time DoorDash driver, $58,000 gross
$58,000 gross − $18,000 mileage/phone = $40,000 net. Contribute $30,800 to Solo 401(k). New AGI ≈ $6,974 after half-SE and 401(k). Federal income tax drops to nearly $0, state tax drops to ~$200. Total tax saved vs no contribution: ~$8,400. SE tax stays the same.
Worked example — part-time freelancer, $15,000 gross
$15,000 net freelance income. Solo 401(k) employee deferral can be 100% of net earnings after SE tax (~$13,850). If you also have a $60k W-2, you're already over the deferral limit and should skip the Solo 401(k) employee side; a SEP-IRA at $2,780 (20%) is the right call.
The bottom line
For 90% of full-time gig workers under $150k net profit, the Solo 401(k) shelters more income than a SEP-IRA — the extra $23,500 employee deferral is impossible to beat. Open one before December 31 to lock in this year's contribution window. Estimate the tax impact with our [self-employed tax estimator](https://gigmytax.com/calculators/self-employed-tax-estimator).
Frequently asked questions
+Can a DoorDash or Uber driver open a Solo 401(k)?
Yes. Any 1099 self-employed person with earned income and no full-time W-2 employees (other than a spouse) qualifies. DoorDash, Uber, Instacart, Grubhub, and Amazon Flex drivers are all eligible.
+Does a Solo 401(k) contribution reduce self-employment tax?
No. Neither Solo 401(k) nor SEP-IRA contributions reduce the 15.3% SE tax — they only reduce federal and state income tax by lowering AGI.
+Can I have both a SEP-IRA and a Solo 401(k) in the same year?
Technically yes, but the IRS treats them as one plan for contribution limits, and rules get messy. Almost every solo self-employed person is better off picking one.
+What's the deadline to open a Solo 401(k) for the 2026 tax year?
December 31, 2026 to establish the plan. Employee deferrals must be elected by year-end (funded by the tax deadline). Employer profit-share funding is due by the filing deadline including extensions (October 15, 2027).
+Do I have to file anything with the IRS for a Solo 401(k)?
Only Form 5500-EZ once plan assets exceed $250,000, and Form 5500-EZ in the final year of the plan. Below the threshold, no annual filing is required.
+Can I contribute to a Roth Solo 401(k)?
Yes. Employee deferrals up to $23,500 can go to a Roth Solo 401(k) at brokerages that offer it (Fidelity, Schwab, E*TRADE). There's no AGI limit — a major advantage over a Roth IRA.
Related calculators
- Self-Employed Tax EstimatorEstimate federal, SE, and state tax for your full 1099 year.
- Side Hustle Tax CalculatorEstimate tax on side-gig 1099 income stacked on your W-2.
- Self-Employment Tax CalculatorCalculate the 15.3% SECA tax on your net 1099 income.
- How Much Should I Save for Taxes?Set-aside % of every 1099 payout for federal, SE, and state tax.
Related guides
- Self-Employment Tax Deductions: The 2026 PlaybookEvery 2026 deduction that lowers self-employment tax — Schedule C write-offs, half-of-SE-tax deduction, SEP-IRA, self-employed health insurance, and QBI.
- Quarterly Taxes for Freelancers: The 2026 GuideHow freelancers pay 2026 quarterly estimated taxes. Due dates, safe-harbor rules, penalty math, and step-by-step instructions using IRS Direct Pay or EFTPS.
- How Much Should I Save for Taxes as a Self-Employed Worker in 2026The exact % of every 1099 payout to save for taxes in 2026. Covers federal, self-employment, and state tax for freelancers, gig workers, and contractors.
- 1099 Tax Guide for Beginners: The 2026 WalkthroughNew to 1099 income? This beginner's guide covers forms, quarterly taxes, deductions, SE tax, and how to file — everything you need for the 2026 tax year.
- The Best Tax Deductions for Gig Workers in 2026The 15 best tax deductions for gig workers in 2026 — mileage, phone, home office, health insurance, retirement, and more. With examples and IRS rules.