Retirement Accounts for Freelancers: SEP IRA vs Solo 401(k) in 2026

For most freelancers, a solo 401(k) shelters far more money than a SEP IRA, and it is not close. The reason is structural. A SEP contribution is capped by a percentage of what you earned, so a smaller income means a smaller contribution. A solo 401(k) lets you contribute a flat dollar amount as the employee first, then add the percentage-based piece on top. Most comparisons treat the two as near equivalents. They are not equivalent until your income gets genuinely high, and the gap in between is worth tens of thousands of dollars a year.

At FreelanceAtlas, we help freelancers make money decisions with the actual numbers in front of them. This guide runs the 2026 limits through three income levels, covers the deadlines that cost people a whole tax year, and explains the paperwork that makes a solo 401(k) more expensive to keep than to open. Read it alongside Freelancer Income Streams: Earn More Without More Hours and How Freelancers Should Manage Money in 2026.

This article is general information, not financial or tax advice. Consult a CPA or a fiduciary financial adviser before making decisions about your own retirement plan.

What the Two Accounts Actually Are

Both are tax-advantaged retirement accounts a self-employed person with no employees can open. The difference is who you are treated as when you contribute.

In a SEP IRA you contribute in one capacity: as the employer. There is no employee side. Your contribution is a percentage of compensation, and that percentage is the only lever you have. Modest compensation means a modest maximum, no matter how much cash you could spare.

In a solo 401(k) you wear two hats. You contribute as the employee through an elective deferral, a flat dollar amount set by statute rather than by a percentage. Then you contribute again as the employer through a profit-sharing contribution, which works much like the SEP. The two stack under one overall ceiling.

That stacking is the argument of this article. The deferral does not care whether you earned $50,000 or $500,000, which makes it proportionally enormous at a low income and trivial at a high one.

The 2026 Numbers, Straight From IRS Notice 2025-67

Every figure below comes from the IRS cost-of-living adjustments for 2026, published in IRS Notice 2025-67.

• Total contribution limit. The IRS sets the Section 415(c) limit at $72,000 for 2026, up from $70,000. It caps employee deferrals plus employer contributions to a single plan.
• Employee elective deferral. The IRS sets the 2026 deferral limit at $24,500, up from $23,500.
• Catch-up at age 50 and over. The IRS sets this at $8,000 for 2026, up from $7,500.
• Catch-up at ages 60 to 63. The IRS keeps this at $11,250 for 2026. It did not rise.
• SEP participation compensation floor. The IRS sets the SEP threshold at $800 for 2026, up from $750.
• Annual compensation limit. The IRS caps compensation any plan formula can count at $360,000 for 2026, up from $350,000.
• IRA limit. The IRS sets the 2026 IRA limit at $7,500, up from $7,000, with a catch-up of $1,100 at age 50 and over, up from $1,000.

Read the ages 60 to 63 figure carefully. Several secondary sites reported it as rising for 2026. It did not. Only the standard catch-up for age 50 and over increased, from $7,500 to $8,000.

Why the SEP’s 25 Percent Is Really About 20 Percent

A SEP is described everywhere as allowing 25 percent of compensation. For a self-employed person that is misleading, and understanding why is the crux of the comparison. IRS Publication 560 states that when you are self-employed, “the deduction for contributions to your own SEP IRA and your net earnings depend on each other.” Because of that circular dependency, the effective maximum is approximately 20 percent of net self-employment earnings, not 25 percent.

Compensation here is not gross revenue and not even net profit. Publication 560 defines it as net earnings from self-employment after subtracting both the deductible part of self-employment tax and the SEP contribution itself. The contribution reduces the number it is measured against.

The Arithmetic Behind the Drop

Call your net earnings before the contribution E, and the contribution X. The 25 percent rule says X equals 25 percent of what is left after the contribution comes out:

X = 0.25 * (E – X)

Multiply out and you get X = 0.25E – 0.25X. Collect the contribution terms and you get 1.25X = 0.25E. Divide both sides by 1.25 and you get X = 0.20E. Twenty-five percent of the reduced base is exactly twenty percent of the base you started with.

Publication 560 handles this for you through the Rate Table and Rate Worksheet for Self-Employed in chapter 5. Every result below uses the 20 percent effective rate and is approximate, because the exact figure depends on your own self-employment tax deduction.

The Comparison at Three Income Levels

Two things to hold in mind. Every figure is approximate, because the deductible part of self-employment tax varies with income. And the base for both plans is identical: net earnings from self-employment after that deduction, which this article calls adjusted net earnings. For how the tax itself is computed, see Freelancer Taxes Made Simple.

At Roughly $60,000 of Net Profit

Net profit of $60,000 leaves adjusted net earnings of roughly $55,800. The SEP allows approximately 20 percent of $55,800, which is about $11,160. That is the maximum, with nothing to add to it.

The solo 401(k) allows the same $11,160 profit-sharing contribution, plus a deferral of up to $24,500, for roughly $35,660. Both figures sit far below the $72,000 ceiling. The solo 401(k) wins by the entire deferral and shelters roughly three times what the SEP does on identical income.

At Roughly $120,000 of Net Profit

Double the income and the direction does not change. Net profit of $120,000 gives adjusted net earnings of roughly $111,500, so the SEP allows approximately 20 percent of that, about $22,300.

The solo 401(k) allows that same $22,300 plus the $24,500 deferral, for about $46,800, still under the ceiling. The gap is again $24,500 in dollars, but the ratio has fallen to roughly two to one. That is what a flat deferral sitting on top of a percentage does as income rises.

At a High Income

Now take adjusted net earnings of about $240,000, which implies a net profit meaningfully higher once the self-employment tax deduction is added back. The SEP allows approximately 20 percent of $240,000, which is $48,000.

The solo 401(k) allows the same $48,000 plus the $24,500 deferral, which is $72,500. That exceeds the Section 415(c) limit, so the contribution is capped at $72,000. The deferral is being clipped. The solo 401(k) still wins, by $24,000 rather than $24,500, but this is the first level where the advantage erodes.

Where the Two Plans Converge

A solo 401(k) reaches the ceiling when $24,500 plus 20 percent of adjusted net earnings equals $72,000. That means 20 percent of adjusted net earnings must be $47,500, so adjusted net earnings of about $237,500.

A SEP reaches $72,000 only when 20 percent of adjusted net earnings equals $72,000 on its own, which needs adjusted net earnings of about $360,000. That sits exactly at the $360,000 annual compensation limit the IRS sets for 2026, so no larger SEP contribution is available above it.

Between roughly $237,500 and roughly $360,000 the solo 401(k) sits at its ceiling while the SEP climbs toward it. Above about $360,000 the two tie at $72,000, before catch-up. The SEP never beats the solo 401(k) on capacity. It only stops losing.

Catch-Up Contributions Change the Ceiling, Not the Logic

At age 50 and over, catch-up contributions sit on top of the Section 415(c) limit rather than inside it, which raises the solo 401(k) ceiling. The arithmetic from the verified 2026 figures:

• Age 50 and over. $72,000 + $8,000 = $80,000.
• Ages 60 to 63 in 2026. $72,000 + $11,250 = $83,250.

Catch-ups are an employee-side feature. A SEP has no employee deferral, so there is no catch-up to add. For a freelancer in their fifties or early sixties compressing a lot of saving into a few years, that is the difference between $72,000 and $83,250 in one year.

Deadlines: Where People Lose the Whole Year

This is the one area where the SEP has a decisive advantage. The IRS states in its SEP retirement plan FAQs that “you can set up a SEP plan for a year as late as the due date (including extensions) of your business’s income tax return for that year.” On funding, the same page states that “you must deposit contributions for a year by the due date (including extensions) for filing your federal income tax return for the year.”

That is unusual. A SEP can be opened after the tax year has already ended and funded on the same timetable. If it is spring, your books are closed and the profit was larger than expected, a SEP can still be established and funded for the year behind you.

A solo 401(k) does not offer that rescue. It generally has to be in place earlier, because the employee deferral depends on a plan existing during the year you were earning. This article will not state a first-year establishment deadline for a solo 401(k), because the rules here have moved in recent years. Confirm the current deadline with your plan provider or CPA before relying on it.

The practical version: set up a solo 401(k) inside the tax year, not after it. If you missed that window, the SEP is very likely still open to you, and a smaller contribution you are allowed to make beats a larger one you are not. See also Quarterly Estimated Taxes for Freelancers, since these dates track your filing timetable.

The Mandatory Roth Catch-Up Rule, and Who It Hits

From 1 January 2026, a participant aged 50 or over whose FICA wages from the employer sponsoring the plan exceeded $150,000 in the prior year must have catch-up contributions designated as Roth. The threshold rose from $145,000 to $150,000 in Notice 2025-67. Roth catch-ups go in after tax, so the immediate deduction disappears.

What follows is analysis, not a statement from the IRS, and it is worth confirming with your own CPA.

The test keys off FICA wages, which are wages reported on a Form W-2. A sole proprietor or single-member LLC running a solo 401(k) normally has no FICA wages from that business, because self-employment earnings are taxed through self-employment tax rather than FICA payroll. On that reading the rule generally does not bind an unincorporated freelancer, whatever the income.

Where it would bite is a freelancer who elected S corporation taxation and pays themselves a W-2 salary above $150,000. That person has real FICA wages from the sponsoring employer. If you are weighing that election, Sole Proprietor vs LLC for Freelancers covers what it changes. Confirm your own position with a CPA.

Layering an IRA on Top of Your Business Plan

Opening a SEP or solo 401(k) does not use up your personal IRA allowance. The IRS sets the 2026 IRA limit at $7,500, with a $1,100 catch-up at age 50 and over, and you can usually contribute to both in the same year.

The catch is deductibility. Opening either plan makes you an active participant in a workplace retirement plan, which triggers the traditional IRA deduction phase-outs. The IRS sets these for 2026 as follows.

• Single and head of household. $81,000 to $91,000.
• Married filing jointly, contributing spouse is the participant. $129,000 to $149,000.
• Married filing jointly, contributor is not a participant but the spouse is. $242,000 to $252,000.
• Married filing separately. $0 to $10,000, fixed rather than inflation adjusted.

Roth IRA eligibility works differently. It is unaffected by workplace plan participation and phases out purely on income. The IRS sets the 2026 ranges at $242,000 to $252,000 for married filing jointly, $153,000 to $168,000 for single and head of household, and a fixed $0 to $10,000 for married filing separately.

So a solo 401(k) can cost you the deduction on a traditional IRA contribution, but it cannot cost you Roth IRA eligibility. Under the Roth income limits, the natural stack is the business plan first, then a Roth IRA on top.

Form 5500-EZ Is the Solo 401(k)’s Real Long-Term Cost

The solo 401(k) wins on capacity and loses on paperwork. The SEP’s advantage was never contribution size. It is administrative simplicity, and that simplicity has a specific name.

According to IRS guidance on one-participant plans, such a plan must file Form 5500-EZ once the combined assets of all one-participant plans the employer maintains exceed $250,000 at plan year end. The deadline is 31 July. Three details matter more than the headline.

• The threshold is combined, not per account. All one-participant plans the employer maintains are added together against the $250,000 figure.
• Once you cross it, the obligation continues. A later fall below $250,000 does not switch the filing requirement back off.
• A final Form 5500-EZ is required on plan termination, regardless of the balance at that point.

None of that is onerous, but it is a recurring annual task with a hard date, and it arrives exactly when the plan has grown large enough to matter. A freelancer who wants a low-maintenance account and is not going to use the deferral anyway has a real reason to prefer a SEP. That is a genuine trade, just not the one most articles describe.

What Changes When You Hire Someone

Both plans change character the moment you have an employee, and this is where you should stop reading articles and get advice.

A SEP generally requires the employer to contribute the same percentage of compensation for every eligible employee as the owner takes. The IRS sets the 2026 SEP participation compensation floor at $800, so an employee earning at least that much can count toward eligibility. A rate that was cheap with one participant becomes expensive across a payroll.

A solo 401(k) stops being a solo plan once you have an eligible employee. Adding staff generally moves you into a full 401(k) plan with the testing, disclosure and administration that go with it.

Both statements describe the general shape of the rules rather than the whole of them, and eligibility carries exclusions and service requirements this article does not enumerate. If hiring is on your horizon, raise it before you choose a plan.

The Decision Rule the Arithmetic Produces

Reasoning from the numbers above rather than from anyone’s advice, the decision falls out in a short sequence.

Below roughly $360,000 of adjusted net earnings, the solo 401(k) shelters more, and the lower your income the bigger that difference is as a share of what you earn. At about $55,800 of adjusted net earnings it is roughly $35,660 against about $11,160. If you can open one in time and will file Form 5500-EZ once the balance passes $250,000, that is where the capacity is.

At or above roughly $360,000, both plans reach $72,000, and the solo 401(k)’s only remaining edge is catch-up capacity at 50 and over. There the SEP’s simplicity becomes a real argument rather than a consolation.

If the tax year has already ended and you have no plan, the sequence collapses to one option. A SEP can still be set up and funded up to your business return due date including extensions.

Conclusion

This is not a close judgment call for most freelancers, and treating it as one costs real money. A SEP is capped at approximately 20 percent of adjusted net earnings. A solo 401(k) adds a flat $24,500 deferral on top of that same contribution, and the difference holds until the $72,000 limit clips it.

Do this in order. Work out your own adjusted net earnings using the Rate Worksheet in Publication 560 rather than an estimate. Decide whether you can realistically fund more than 20 percent of it, because if you cannot, the SEP’s simplicity may be worth more than headroom you will never use. If you can, confirm the current solo 401(k) establishment deadline with a provider or CPA and open it inside the tax year. Then add an IRA on top if your income sits under the Roth ranges.

Key Takeaways

• A solo 401(k) shelters far more than a SEP IRA at low and middle incomes, because the $24,500 employee deferral the IRS set for 2026 is a flat dollar amount that stacks on top of the percentage-based employer contribution.
• The SEP’s advertised 25 percent works out to approximately 20 percent of net self-employment earnings, because IRS Publication 560 states that the deduction for contributions to your own SEP IRA and your net earnings depend on each other.
• At about $55,800 of adjusted net earnings a SEP allows roughly $11,160 while a solo 401(k) allows roughly $35,660, and the two do not reach the same ceiling until adjusted net earnings approach $360,000.
• The IRS sets the 2026 total limit at $72,000, giving $72,000 + $8,000 = $80,000 at age 50 and over and $72,000 + $11,250 = $83,250 at ages 60 to 63, since the enhanced catch-up did not rise.
• A SEP can be set up and funded as late as the due date of your business income tax return including extensions, while a solo 401(k) generally has to be in place earlier, so confirm that deadline with your provider or CPA.
• A solo 401(k) triggers an annual Form 5500-EZ filing once combined one-participant plan assets exceed $250,000 at plan year end, and that obligation continues even if the balance later falls.

Frequently Asked Questions