Solo 401(k) vs SEP IRA 2026: Which Retirement Plan is Best for the Self-Employed?

Retirement Options for the Self-Employed

When you're self-employed, you don't get an employer-sponsored 401(k) with a match. That means building retirement savings is entirely on you. The good news? Two powerful tax-advantaged retirement plans exist specifically for solo business owners, freelancers, and independent contractors: the Solo 401(k) and the SEP IRA.

Both allow you to save significantly more than a traditional IRA (which caps at $7,000 for 2026) and both offer immediate tax deductions on contributions. But they work differently, and the right choice depends on your income, business structure, and retirement goals.

In this guide, we break down the 2026 contribution limits, deadlines, eligibility rules, and strategic advantages of each plan. Use our self-employed retirement calculator to compare both plans side-by-side with your actual numbers.

Solo 401(k): Contribution Limits & Features for 2026

The Solo 401(k) (also called an Individual 401(k) or Self-Employed 401(k)) is a retirement plan designed for business owners with no employees other than a spouse. It combines features of a traditional 401(k) with the flexibility of an IRA. For 2026, the Solo 401(k) offers some of the highest contribution limits available to self-employed individuals.

2026 Contribution Limits

The Solo 401(k) has a two-part contribution structure that mirrors what you'd get as both employee and employer at a traditional job:

• Employee deferral: Up to $23,500 for 2026 (the same as a standard 401(k)). This is money you choose to defer from your compensation.
• Catch-up contribution (age 50+): An additional $7,500, bringing the employee deferral max to $31,000 for those 50 or older.
• Employer profit-sharing: Up to 25% of net self-employment income (calculated after deducting half of self-employment tax and the employee deferral itself).
• Total limit: The combined employee + employer contributions cannot exceed $70,000 for 2026 ($77,500 with catch-up).

What makes the Solo 401(k) especially powerful is that the employee deferral portion does not count toward the 25% employer calculation limit. This effectively allows you to contribute a much higher percentage of your income at lower earnings levels compared to a SEP IRA.

Roth Option

One major advantage of the Solo 401(k) is the ability to elect Roth contributions. Roth deferrals are made with after-tax dollars but grow tax-free, and qualified withdrawals in retirement are completely tax-free. This is valuable if you expect to be in a higher tax bracket later in life or want to diversify your tax exposure in retirement.

The SEP IRA does not offer a Roth option — all SEP IRA contributions are pre-tax.

Loan Feature

Solo 401(k) plans can allow loans of up to $50,000 or 50% of your vested balance (whichever is less). This can serve as an emergency liquidity source without triggering taxes or penalties, as long as you repay the loan according to the plan terms. The SEP IRA does not permit loans.

Deadline to Open & Contribute

You must open the Solo 401(k) by December 31, 2026 (the plan must exist by the last day of the tax year). However, you can make employee deferrals and employer profit-sharing contributions up until your tax filing deadline, including extensions (typically April 15, 2027, or October 15, 2027 with an extension).

SEP IRA: Contribution Limits & Features for 2026

The SEP IRA (Simplified Employee Pension IRA) is a retirement plan that allows self-employed individuals and small business owners to make contributions on behalf of themselves and their employees. For solo operators with no employees, the SEP IRA is simpler to administer than a Solo 401(k) but has different contribution mechanics.

2026 Contribution Limits

The SEP IRA uses a single calculation based on your net earnings from self-employment:

• Contribution rate: Up to 25% of your net self-employment income (or 20% of your net profit if you're a sole proprietor, due to the self-employment tax deduction adjustment).
• Maximum contribution: The absolute cap for 2026 is $70,000, matching the Solo 401(k) total limit.
• No catch-up contributions: Unlike the Solo 401(k), the SEP IRA does not offer additional catch-up contributions for those aged 50 or older.

Unlike the Solo 401(k), SEP IRA contributions are made solely by the employer (you, as the business owner). There is no employee salary deferral option. All contributions are tax-deductible as a business expense.

Deadline to Open & Contribute

The SEP IRA is more flexible than the Solo 401(k) on timing. You can open and fund a SEP IRA up until your tax filing deadline, including extensions. This means you could open a SEP IRA as late as April 15, 2027 (or October 15, 2027 with a filing extension) and still have it count for the 2026 tax year. However, you must contribute by that same deadline — no grace period beyond filing.

Administrative Simplicity

The SEP IRA is significantly easier to set up and maintain. There are no annual filing requirements (no Form 5500-EZ), no plan document amendments needed each year, and most financial institutions offer SEP IRAs with zero setup costs. If administrative simplicity is your priority, the SEP IRA wins hands down.

Comparison Table: Solo 401(k) vs SEP IRA 2026

To see how each plan stacks up with your specific numbers, try our self-employed retirement plan calculator for a detailed side-by-side comparison.

Which Plan Should You Choose?

The right choice depends on your income level, age, business structure, and how much administrative work you're willing to handle. Here is our recommendation framework based on common scenarios:

Choose the Solo 401(k) if:

• You earn less than ~$280,000 in net self-employment income. The employee deferral lets you save more at lower income levels.
• You want Roth contributions. The ability to make after-tax Roth deferrals is a powerful tool for tax diversification.
• You may need a loan from your retirement account for emergencies or business investments.
• You are 50 or older and want to take advantage of the $7,500 catch-up contribution.
• You have no employees (other than a spouse). Adding employees to a Solo 401(k) is complicated.

Choose the SEP IRA if:

• You value simplicity. The SEP IRA takes 15 minutes to set up and has no annual filing requirements.
• You earn more than ~$280,000 in net income and can hit the $70,000 cap easily through the 25% employer contribution alone.
• You might hire employees in the future. SEP IRAs cover employees more simply (though you must contribute the same percentage for them).
• You missed the Dec 31 Solo 401(k) deadline — you can open a SEP IRA up to your tax filing deadline.
• You want the lowest possible administrative burden with no Form 5500-EZ to file, ever.

How Contributions Reduce Taxable Income

Both the Solo 401(k) and SEP IRA offer powerful tax benefits by reducing your adjusted gross income (AGI) dollar for dollar on pre-tax contributions. Here is how the mechanics work:

Immediate Tax Deduction

Every dollar you contribute to a traditional Solo 401(k) or SEP IRA is deducted from your self-employment income on Schedule 1 of Form 1040. This means:

• You pay no federal income tax on the contributed amount in the current year.
• You pay no self-employment tax on the contributed amount either — this is because the contribution is an adjustment to income that reduces your net earnings from self-employment.
• Your contribution may lower your tax bracket or keep you in a lower bracket, reducing your marginal tax rate on every additional dollar of income.

Real-World Tax Savings Example

Consider a freelance web developer earning $150,000 in net self-employment income who contributes $35,000 to a Solo 401(k):

• Without contribution: Pays roughly $24,000 in federal income tax + $11,500 in self-employment tax = $35,500 total.
• With $35k Solo 401(k) contribution: Taxable income drops to ~$115,000. Federal tax falls to ~$16,500 and self-employment tax to ~$8,800 = $25,300 total.
• Tax savings: ~$10,200 in one year. And the $35,000 grows tax-deferred until retirement.

Run your own numbers with our retirement tax savings calculator to see exactly how much you can save based on your specific income and contribution level.

Compound Growth Advantage

The real magic of retirement accounts is tax-deferred (or tax-free, with Roth) compound growth. A $35,000 annual contribution earning 7% annually could grow to over $1.4 million in 20 years. Without the tax deduction, you'd have less to invest, and taxes on annual gains would erode your returns in a taxable account. The quarterly tax calculator can help you estimate how retirement contributions affect your quarterly estimated tax payments throughout the year.

Frequently Asked Questions

Can I have both a Solo 401(k) and a SEP IRA?
Yes, but there are limits. You cannot exceed the combined annual contribution limits across all retirement plans. If you have a Solo 401(k) from a consulting business and a SEP IRA from a separate sole proprietorship, the $70,000 total limit applies across both plans. You'd need to coordinate contributions to stay under the combined cap. In practice, most people pick one or the other.

What happens if I hire an employee?
With a Solo 401(k), you generally cannot have any employees other than a spouse. If you hire a non-spouse employee, you may need to switch to a different plan or cover them under the same plan (which requires passing nondiscrimination testing). A SEP IRA accommodates employees more easily — you simply contribute the same percentage of compensation for each eligible employee as you do for yourself.

Can I contribute to a SEP IRA and a Roth IRA in the same year?
Yes. A SEP IRA does not affect your ability to contribute to a traditional or Roth IRA (the $7,000 limit is separate). However, your Roth IRA contribution may be phased out if your modified AGI exceeds certain thresholds ($146,000-$161,000 for single filers in 2026). Likewise, you can have a Solo 401(k) and still contribute to a Roth IRA if you meet income limits.

Which plan has lower fees?
Both can have very low fees. Most major brokerages (Vanguard, Fidelity, Schwab, etc.) offer Solo 401(k)s and SEP IRAs with no setup fees and access to low-cost index funds. SEP IRAs tend to have slightly lower administrative costs because there are no annual filing requirements. A Solo 401(k) with a balance over $250,000 requires filing Form 5500-EZ annually, which may involve a small fee if you use a third-party filing service.

Is there an income limit for contributing to a Solo 401(k) or SEP IRA?
No income limits. Unlike a Roth IRA, which phases out at higher income levels, both the Solo 401(k) and SEP IRA allow contributions at any income level. The only limit is the maximum contribution cap and the percentage-of-income calculation. This makes both plans ideal for high-earning freelancers and consultants.

Can I withdraw money early from a Solo 401(k) or SEP IRA?
Yes, but early withdrawals before age 59½ are subject to ordinary income tax plus a 10% early withdrawal penalty. There are exceptions for disability, medical expenses, and certain other hardship situations. Solo 401(k) loans are an alternative — you can borrow up to $50,000 without triggering taxes or penalties. SEP IRAs do not offer loans. Our retirement calculator can help you model the long-term impact of early withdrawals.

Do I need to file Form 5500-EZ for a Solo 401(k)?
Only if your plan's assets exceed $250,000 at the end of the year. The form is relatively straightforward (reporting plan assets and participant counts) but failure to file can result in significant penalties ($250 per day, up to $15,000). Many Solo 401(k) providers offer guidance or automatic filing assistance. SEP IRAs have no equivalent filing requirement, which is a key advantage for simplicity.

What happens to my Solo 401(k) or SEP IRA if I close my business?
You can leave the funds in place, roll them over to an IRA, or roll the Solo 401(k) into a new employer's plan if applicable. For a SEP IRA, you can simply leave it as a traditional IRA — it converts to an IRA you control independently of any business. For a Solo 401(k), you must formally terminate the plan and distribute or roll over assets. The IRS requires a plan termination resolution and final Form 5500-EZ filing if assets exceed $250,000.