SEP IRA vs Solo 401(k): Which Self-Employed Retirement Plan Saves You More in 2026?

As a freelancer or independent contractor, you do not have an employer matching your 401(k) contributions. But you have something potentially better: the ability to choose your own retirement plan with contribution limits that can be far higher than what regular employees get. The two most popular options for self-employed individuals are the SEP IRA and the Solo 401(k) (also called an individual 401(k) or one-participant 401(k)).

Both plans let you stash away a significant portion of your freelance income tax-deferred, which means every dollar you contribute reduces your current-year taxable income. For a freelancer in the 24% federal tax bracket, contributing $30,000 to a retirement plan saves approximately $7,200 in federal income tax — plus state tax savings if applicable. That is real money back in your pocket.

But the two plans are not interchangeable. They have different contribution structures, different deadlines, different costs, and different rules. Choosing the wrong one could mean leaving thousands of dollars in tax savings on the table — or paying for a plan you do not need.

This guide breaks down everything you need to know: the 2026 contribution limits, how contributions are calculated, Roth options, loan features, setup costs, and — most importantly — which plan makes sense based on your income level and goals.

How Each Plan Works: The Basics

SEP IRA (Simplified Employee Pension)

A SEP IRA is the simplest self-employed retirement plan. You open an account at any major brokerage (Fidelity, Vanguard, Schwab, E*TRADE), and you are done. There are no setup fees, no annual filing requirements, and no complex administrative paperwork. Contributions are made as the employer — there is no separate employee deferral component.

The contribution formula is straightforward: you can contribute up to 25% of eligible compensation (the effective rate for a sole proprietor is lower after the self-employment tax adjustment), subject to an annual dollar cap. The defined-contribution limit is $72,000 for 2026.

One key feature: if you ever hire employees, a SEP IRA requires you to contribute the same percentage of compensation for all eligible employees. This makes it less attractive for freelancers who plan to grow their business and add staff.

Solo 401(k) (Individual 401(k))

A Solo 401(k) is a more powerful but slightly more complex plan. It is designed specifically for self-employed individuals and business owners with no full-time employees other than themselves and their spouse. The defining feature: you contribute in two roles — as the employee and as the employer — which effectively doubles your contribution capacity at lower income levels.

As the employee, you can defer up to $24,500 in 2026 of earned income, plus a catch-up contribution if eligible ($8,000 in 2026 for most participants age 50 or older, or $11,250 at ages 60 to 63). As the employer, you can make an additional contribution subject to plan rules. The combined employee-plus-employer limit is $72,000 for 2026, before eligible catch-up contributions.

A Solo 401(k) requires a bit more setup: you need to adopt a written plan document (most brokerages provide this for free), obtain an EIN if you do not have one, and file Form 5500-EZ annually once your plan assets exceed $250,000. Below that threshold, no annual filing is required.

SEP IRA vs Solo 401(k) Limits at a Glance (2026)

For the full 2026 dollar limit for every plan and every age band, see our complete guide to self-employed retirement contribution limits in 2026.

The Contribution Math: Why Income Level Matters

The critical difference between these two plans is how contributions are calculated. The Solo 401(k)'s employee deferral component means you can contribute more at lower income levels. Here is why that matters.

With a SEP IRA, your contribution is purely employer-based: 25% of your compensation. For a sole proprietor, compensation is net profit after the deductible half of self-employment tax, so the effective rate works out to approximately 20% of that figure. So if you earn $100,000 in net profit, your SEP IRA contribution is roughly $18,587, not $20,000.

With a Solo 401(k), you get the employee deferral first — $24,500 for 2026 — plus the same employer contribution of 25% of compensation. So if you earn $100,000 in net profit, you can contribute $24,500 as the employee, plus approximately $18,587 as the employer, for a total of about $43,087. That is more than double the SEP IRA contribution at the same income level.

The difference is even more dramatic at lower incomes:

As the table makes clear, the Solo 401(k) advantage is $24,500 at every income level up to approximately $280,000. That is because the employee deferral ($24,500 in 2026) is available to the Solo 401(k) participant but does not exist in the SEP IRA. Only at very high incomes (approximately $376,500+) do both plans max out at the same $72,000 cap.

What does that extra $24,500 mean in tax savings? At a 24% federal marginal rate, it saves an additional $5,880 in federal income tax. Add state tax savings (for example, 5% in a typical state-income-tax state) and the total tax savings from choosing a Solo 401(k) over a SEP IRA can exceed $7,100 per year — year after year, compounding tax-deferred until retirement.

Roth Contributions: A Solo 401(k) Exclusive

One of the biggest advantages of the Solo 401(k) is the ability to make Roth (after-tax) contributions. A SEP IRA only accepts pre-tax (traditional) contributions — there is no Roth option. This is a significant limitation if you expect your tax rate in retirement to be higher than your current rate, or if you want tax diversification.

With a Roth Solo 401(k), you contribute after-tax dollars. The money grows tax-free, and qualified withdrawals in retirement (after age 59.5, with a 5-year holding period) are completely tax-free — including all investment gains. For a freelancer who is currently in a lower tax bracket but expects to earn significantly more in the future, or who anticipates higher tax rates decades from now, the Roth Solo 401(k) can be a powerful long-term strategy.

You can even split your contributions between traditional (pre-tax) and Roth (after-tax) within the same Solo 401(k) plan. For example, you might contribute $12,000 as a traditional deferral (to get an immediate tax deduction) and $11,500 as a Roth deferral (to build tax-free retirement income). This gives you tax diversification — some money taxed now, some money taxed never.

A SEP IRA cannot do this. All contributions are pre-tax, and all withdrawals in retirement are taxed as ordinary income. The only way to get Roth money from a SEP IRA is to do a Roth conversion (contribute pre-tax, then convert to a Roth IRA), which triggers a taxable event in the year of conversion.

Loan Feature: Borrowing from Your Retirement

The Solo 401(k) allows you to take a plan loan of up to 50% of your vested account balance or $50,000, whichever is less. You pay yourself back with interest (typically the prime rate plus 1%), and the interest goes back into your own account — you are essentially paying yourself to borrow your own money.

The SEP IRA does not allow loans. If you need access to your funds before age 59.5, you would have to take a distribution, which triggers income tax plus a 10% early withdrawal penalty (unless you qualify for an exception). This makes the Solo 401(k) more attractive for freelancers who want a safety valve for emergencies without permanently depleting their retirement savings.

Setup Costs and Administrative Requirements

Cost and complexity are where the SEP IRA has traditionally held the advantage. Here is how the two plans compare:

The gap in cost has narrowed significantly in recent years. Major brokerages like Fidelity, Vanguard, and Schwab now offer Solo 401(k) plans with $0 setup fees and no annual maintenance costs. The main remaining complexity is the plan document adoption and the potential Form 5500-EZ filing — but for most freelancers with plan assets under $250,000, the filing requirement does not even apply.

However, the SEP IRA still wins decisively on simplicity. You can open one online in 15 minutes with just your Social Security number. No EIN, no plan document, no annual filings — ever. For freelancers who want the absolute minimum administrative overhead, the SEP IRA remains the easiest option.

Contribution Deadlines: A Critical Difference

This is where many freelancers get tripped up. The two plans have different deadlines for making contributions, and getting this wrong can cost you a year of tax savings.

SEP IRA deadline

You can open and fund a SEP IRA up to the original tax filing deadline (April 15 for most individuals). If you file an extension, you have until October 15 to open the account and make contributions for the prior tax year. This makes the SEP IRA ideal for last-minute tax planning — you can reduce your 2025 tax bill as late as October 15, 2026, as long as you filed your extension by April 15, 2026.

Solo 401(k) deadline

This is the critical catch: while you can make employer contributions to a Solo 401(k) up to the tax filing deadline (including extension, so October 15), the employee deferral portion ($23,500 for 2025, $24,500 for 2026) must be elected and contributed by December 31 of the tax year. If you are reading this in March 2026 and have not yet opened a Solo 401(k), you cannot make the employee deferral for the 2025 tax year — that window closed on December 31, 2025. You can still make the employer contribution portion by April 15 (or October 15 with an extension), but you lose the larger employee deferral.

The SEP IRA has no such restriction. You can open the account and make the full contribution as late as October 15 (with an extension) and still get the full tax deduction for the prior year. This makes the SEP IRA a better option for procrastinators who decide to save for retirement at the last minute.

Which Plan Is Right for You? Decision Framework

Based on everything above, here is a practical decision framework:

Choose a Solo 401(k) if:

• Your net self-employment income is under ~$376,500 and you want to maximize contributions
• You want Roth (after-tax) contributions for tax-free retirement withdrawals
• You want the ability to take a loan from your retirement account
• You are under 50 and can benefit from the $24,500 employee deferral for 2026
• You are between 60 and 63 and can use the super catch-up of $11,250 in 2026
• You do not plan to hire full-time employees

Choose a SEP IRA if:

• Your net self-employment income is above ~$376,500 (both plans max out at the same $72,000)
• You want the simplest possible setup with zero ongoing administration
• You might hire employees and do not want the obligation of matching their contributions (SEP IRA requires equal percentage contributions for all eligible employees, but the percentage is your choice each year)
• You missed the December 31 Solo 401(k) employee deferral deadline and need to make a contribution for the prior tax year
• You have a side business with W-2 income from another employer and want to keep things simple

Can you have both?

Technically yes, but it is rarely advantageous. If you have both a SEP IRA and a Solo 401(k), the total employer contribution across both plans cannot exceed 25% of your compensation, and the combined total cannot exceed the annual cap ($72,000 for 2026). The employee deferral from the Solo 401(k) is separate. Having both plans adds complexity without additional tax benefits in most cases. Stick with one unless a tax professional advises otherwise.

Tax Savings Example: Real Numbers for a Real Freelancer

Let us put it all together with a concrete example. Meet Sarah, a freelance graphic designer:

By choosing a Solo 401(k) over a SEP IRA, Sarah saves an additional $6,815 in taxes in a single year while putting $23,500 more into her retirement account. Over 20 years at a 7% average return, that extra $23,500 per year grows to approximately $960,000 in additional retirement savings — and every dollar of growth is tax-deferred (or tax-free if she uses the Roth option).

This is not a marginal optimization. For freelancers earning $50,000-$300,000 in net profit, the choice between a SEP IRA and a Solo 401(k) can represent tens of thousands of dollars in tax savings over a career.

The QBI Deduction Interaction

Retirement contributions also interact with the Qualified Business Income (QBI) deduction — which the OBBBA made permanent at 20% in July 2025. Here is how it works:

Both SEP IRA and Solo 401(k) contributions reduce your net business profit for income tax purposes. Since the QBI deduction is calculated as 20% of your qualified business income (net profit minus retirement contributions and the deductible half of SE tax), making retirement contributions actually reduces your QBI deduction.

For example, if your net Schedule C profit is $100,000 and you contribute $20,000 to a retirement plan, your QBI-eligible income drops to approximately $75,000 (after the SE tax deduction and retirement contribution). Your QBI deduction becomes approximately $15,000 instead of $20,000 — a reduction of about $5,000 in the QBI deduction.

However, the retirement contribution itself saves you far more in tax than the lost QBI deduction. At a 24% bracket, a $20,000 retirement contribution saves $4,800 in income tax. The lost $5,000 QBI deduction costs only $1,200 (24% of $5,000). The net tax savings from the retirement contribution is still $3,600 — plus the $5,000 you saved is growing tax-deferred for retirement. The math overwhelmingly favors making retirement contributions regardless of the QBI interaction.

Where to Open Your Plan

Both SEP IRAs and Solo 401(k)s are available from major brokerages. Here are the most popular options:

• Fidelity: Offers both SEP IRA and Solo 401(k) with $0 setup fees, no minimums, and no annual maintenance costs. The Fidelity Solo 401(k) supports Roth contributions and loan features. Recommended for most freelancers.
• Vanguard: Offers SEP IRA with no fees. Vanguard's Solo 401(k) (Individual 401(k)) requires a $20 setup fee and has a $20 annual fee per fund (waived with electronic statements). Investment options include low-cost Vanguard index funds.
• Schwab: Offers both plans with no setup or maintenance fees. The Schwab Solo 401(k) supports Roth contributions and self-directed investing.
• E*TRADE: Offers a no-fee Solo 401(k) with Roth capability. Good option if you want access to a wide range of investment options including stocks, ETFs, and mutual funds.
• Solo 401(k) specialists (e.g., Nabers, MySolo401k): These providers offer self-directed Solo 401(k) plans that allow alternative investments (real estate, crypto, private equity). Setup costs range from $100-$600, with annual fees of $100-$300. Best for sophisticated investors who want investment flexibility beyond standard brokerage offerings.

For most freelancers, the choice of brokerage matters less than the choice of plan type. The contribution limits and tax benefits are identical regardless of provider. Focus on low fees, investment options you are comfortable with, and whether the provider offers Roth contributions if you want that feature.

Take Action: Open Your Plan Before December 31

If there is one action item from this guide, it is this: do not wait until tax season to think about retirement contributions. If you choose a Solo 401(k), you must open the plan and elect your employee deferral by December 31 of the tax year. If you choose a SEP IRA, you have until the tax filing deadline (April 15 or October 15 with an extension), but why wait? Every month you delay is a month your money is not growing tax-deferred.

Here is a simple action plan:

1. Calculate your net SE income for the year (estimated). Use your Schedule C or profit and loss statement.
2. Decide between SEP IRA and Solo 401(k) based on your income level and goals. Use the decision framework above.
3. Open the account at a brokerage (Fidelity, Vanguard, Schwab, or E*TRADE). For Solo 401(k), make sure to do this before December 31 to preserve your employee deferral election.
4. Make your contribution — either during the year (recommended) or by the tax filing deadline.
5. Report the contribution on your tax return. SEP IRA contributions go on Schedule 1, line 16. Solo 401(k) employee deferrals are reported on Schedule 1, line 13; employer contributions on Schedule 1, line 16.

Retirement contributions are one of the few tax strategies where you save money and build wealth at the same time. Every dollar you contribute reduces your current tax bill while compounding for your future. For a freelancer, choosing the right plan is not just a tax decision — it is one of the most important financial decisions you will make. It also moves your MAGI, which is the number the ACA uses to size a premium tax credit — see how pre-tax retirement contributions protect your ACA subsidy.

Ready to See Your Tax Savings?

Use our free Self-Employment Tax Calculator to estimate your tax liability, then compare how much you could save by contributing to a SEP IRA versus a Solo 401(k). The tool shows your effective tax rate before and after retirement contributions, so you can see the exact dollar impact of each plan.

Sources

This guide draws on the following primary sources from the IRS and other U.S. government agencies. Figures are current for the 2026 tax year and are reviewed each time the IRS publishes updated inflation adjustments.

• IRS Notice 2025-67, 2026 Retirement Plan Contribution Limits
• IRS Publication 560, Retirement Plans for Small Business
• IRS, Retirement Topics — 401(k) and Profit-Sharing Plan Contribution Limits
• IRS, One-Participant 401(k) Plans
• IRS, Retirement Topics — IRA Contribution Limits