Self-Employed Retirement Plans: SEP IRA vs Solo 401(k)

Choosing the right retirement plan is one of the highest-value tax decisions a self-employed person can make. The contribution you put away today reduces your taxable income dollar-for-dollar, grows tax-deferred (or tax-free with Roth), and compounds for decades.

But most self-employed individuals either pick the wrong plan or don’t contribute enough. A freelancer earning $150,000 might default to a SEP IRA and contribute $37,500, not realizing a Solo 401(k) would let them contribute $62,000 in the same year. That’s $24,500 more in tax-deferred savings and roughly $5,880 in immediate tax savings at the 24% bracket.

The three main options are the SEP IRA, Solo 401(k), and SIMPLE IRA. Each has different contribution limits, Roth options, loan provisions, and administrative requirements. This guide breaks down exactly how they compare so you can pick the plan that fits your income, entity type, and long-term goals.

What’s the best retirement plan for self-employed individuals?

For most self-employed individuals earning over $60,000, the Solo 401(k) is the strongest option. It allows up to $72,000 in total 2026 contributions ($24,500 employee elective deferral + employer profit-sharing up to 25% of net self-employment earnings), includes a Roth contribution option, and permits plan loans up to $50,000. The SEP IRA is simpler to administer but caps contributions at 25% of net SE earnings with no Roth option. The SIMPLE IRA works best for lower-income earners but has the lowest contribution ceiling at $17,000 employee/$21,000 with catch-up for 50+. Your ideal plan depends on your net income, whether you have employees, and whether you want Roth access or loan provisions.

Key Takeaways

• Solo 401(k) maximizes contributions for most – Up to $72,000 total for 2026 ($80,000 if 50+), with both employee and employer contribution components
• SEP IRA is the simplest to set up – One form, no annual filing until assets hit $250,000, but limited to 25% of net SE earnings with no Roth option
• SIMPLE IRA has the lowest ceiling – $17,000 employee deferral for 2026 ($21,000 if 50+), best suited for businesses with employees earning under $100,000
• Roth option is only available in the Solo 401(k) – Neither SEP IRA nor SIMPLE IRA offers Roth contributions (SEP Roth was authorized in SECURE 2.0 but few custodians support it yet)
• S-Corp owners get an extra advantage – Running retirement contributions through an S-Corp payroll lets you deduct employer contributions as a business expense while reducing FICA-taxable wages
• Plan choice depends on income level – Below $60,000, any plan works; above $150,000, the Solo 401(k) pulls significantly ahead on contribution capacity

Side-by-Side Comparison: SEP IRA vs Solo 401(k) vs SIMPLE IRA (2026)

A note on the math: For a sole proprietor, “25% of net SE earnings” means 25% of your net profit after deducting half of self-employment tax. On $200,000 of Schedule C net profit, your net SE earnings are roughly $185,860, so your maximum employer contribution is about $46,465. With a Solo 401(k), you’d add the $24,500 employee deferral on top, totaling $70,965. A SEP IRA caps at $46,465.

How Each Plan Works

SEP IRA (Simplified Employee Pension)

The SEP IRA is the go-to plan for self-employed individuals who want simplicity. You fill out IRS Form 5305-SEP, open an account at any brokerage, and make contributions. There’s no annual filing requirement until plan assets exceed $250,000.

How contributions work: All contributions are employer contributions. You contribute up to 25% of your net self-employment earnings, maxing out at $72,000 for 2026. There’s no employee deferral component. This means you need roughly $288,000 in net SE earnings to hit the $72,000 cap.

The catch: If you have W-2 employees, you must contribute the same percentage for them. Contributing 15% of your own earnings means 15% for every eligible employee, too. This makes SEP IRAs expensive for businesses with staff.

Best fit: Solo business owners who want minimal paperwork, don’t need Roth access, and earn enough that 25% of net SE earnings provides sufficient retirement savings.

Solo 401(k)

The Solo 401(k), also called an individual 401(k), is the most flexible retirement plan for self-employed individuals without employees (other than a spouse). It combines an employee deferral with an employer profit-sharing contribution.

How contributions work: You wear two hats. As an employee, you defer up to $24,500 (2026). As the employer, you contribute up to 25% of net SE earnings. The combined total can’t exceed $72,000 ($80,000 if you’re 50 or older, $83,250 for ages 60-63 under the SECURE 2.0 super catch-up).

Why this matters at lower incomes: A freelancer earning $80,000 net SE can contribute $24,500 as an employee deferral plus approximately $18,570 as employer profit-sharing, totaling about $43,070. Under a SEP IRA, the same person maxes out at $18,570. That’s $24,500 less in tax-deferred savings.

Roth option: Solo 401(k) plans can include a designated Roth account. Employee deferrals can go into the Roth bucket (after-tax contributions, tax-free growth and withdrawals). This is valuable for younger business owners or anyone expecting higher tax rates in the future. For more on this strategy, see our Solo 401(k) Roth guide.

Loans: You can borrow up to $50,000 or 50% of your vested balance (whichever is less) from a Solo 401(k). This provides emergency liquidity without triggering taxes or penalties. SEP and SIMPLE IRAs don’t allow loans.

The trade-off: More administrative work. You’ll need to file Form 5500-EZ once plan assets exceed $250,000. The plan must be established by December 31 of the tax year you want to claim the deduction (contributions can be made until your filing deadline). Some custodians charge annual plan fees.

Best fit: Self-employed individuals without employees who want maximum contribution capacity, Roth access, or loan provisions. Especially valuable at income levels between $60,000 and $250,000 where the employee deferral component makes a significant difference.

SIMPLE IRA (Savings Incentive Match Plan for Employees)

The SIMPLE IRA is designed for small businesses with 100 or fewer employees. It’s simpler than a traditional 401(k) but has lower contribution limits than both the SEP IRA and Solo 401(k).

How contributions work: Employees (including the owner) defer up to $17,000 for 2026 ($21,000 if 50+). The employer either matches employee contributions dollar-for-dollar up to 3% of compensation, or makes a 2% non-elective contribution for all eligible employees regardless of whether they contribute.

The limitation: Total contributions are significantly lower. Even with the 3% match, a self-employed individual earning $150,000 would max out around $21,500. Compare that to $61,000+ in a Solo 401(k) at the same income.

Setup deadline: SIMPLE IRAs must be established by October 1 of the tax year. Miss that deadline, and you’re looking at a SEP IRA or Solo 401(k) instead.

Best fit: Small businesses with employees where the owner wants a straightforward retirement benefit for the team and doesn’t need to maximize personal contributions.

Decision Framework: Which Plan Fits Your Situation?

By Income Level

Under $60,000 net SE earnings: Any plan works, but the Solo 401(k) still wins on flexibility. The $24,500 employee deferral alone covers most of what you’d want to contribute. A SEP IRA contribution at 25% of ~$55,700 net SE earnings would be about $13,925, almost $10,575 less.

$60,000-$150,000 net SE earnings: Solo 401(k) is the clear winner. The employee deferral plus employer contribution provides substantially higher contribution capacity than a SEP IRA. At $100,000 net profit (~$92,935 net SE earnings), the Solo 401(k) allows about $47,734 vs. the SEP’s $23,234.

$150,000-$280,000 net SE earnings: Solo 401(k) still leads, but the gap narrows as employer contributions grow. Both plans approach the $72,000 cap. The Solo 401(k) gets there sooner because of the employee deferral.

Above $288,000 net SE earnings: Both SEP IRA and Solo 401(k) hit the $72,000 cap. The Solo 401(k) still wins on Roth access and loan provisions, but pure contribution capacity is identical. At this income, consider adding a Cash Balance Plan (a defined benefit plan) on top to shelter $100,000-$300,000+ annually.

By Entity Type

Sole proprietor / Single-member LLC: Solo 401(k) or SEP IRA. If you value simplicity above all else, go SEP. If you want maximum contributions or Roth access, go Solo 401(k).

S-Corporation: This is where retirement planning gets powerful. As an S-Corp owner-employee, your employer contribution (up to 25% of W-2 wages) is deductible as a business expense and not subject to FICA tax. Your employee deferral reduces your W-2 income for income tax purposes. Combined with reasonable compensation optimization, you can shelter a significant portion of your income.

For example, an S-Corp owner paying themselves $120,000 in W-2 wages could contribute $24,500 as an employee deferral plus $30,000 as an employer contribution (25% of $120,000), totaling $54,500 in tax-advantaged retirement savings. The $30,000 employer contribution is a deductible business expense that also reduces the S-Corp’s taxable income.

Partnership / Multi-member LLC: Each partner contributes based on their guaranteed payments and/or distributive share. A Solo 401(k) can work if the partnership has no common-law employees. Otherwise, consider a SEP IRA or traditional 401(k).

By Life Stage

Under 40: Prioritize the Solo 401(k) with Roth contributions. You have decades of tax-free growth ahead. Even if your income is modest now, the Roth component is worth the extra administrative work.

40-55: Maximize total contributions. If your income supports it, consider layering a Cash Balance Plan on top of a Solo 401(k) to shelter $200,000+ annually.

55+: Take advantage of catch-up contributions ($8,000 extra in a Solo 401(k), $4,000 in a SIMPLE IRA). If you’re 60-63, the SECURE 2.0 super catch-up allows $11,250 extra in a Solo 401(k). Time is shorter, so maximizing current-year deductions matters more.

The S-Corp + Solo 401(k) Strategy

S-Corp owners have a unique opportunity to combine entity-level tax savings with retirement plan benefits. Here’s why this combination works so well.

Step 1: Set reasonable compensation. Your W-2 salary is the basis for both FICA taxes and retirement contributions. Too low, and the IRS can reclassify distributions as wages. Too high, and you pay unnecessary payroll tax. The right number balances compliance with optimization.

Step 2: Maximize the Solo 401(k). Contribute $24,500 as an employee deferral (reducing your W-2 for income tax purposes) and up to 25% of your W-2 wages as an employer profit-sharing contribution (deductible business expense, not subject to FICA).

Step 3: Coordinate with distributions. S-Corp distributions above your reasonable compensation aren’t subject to FICA but are subject to income tax. By maximizing retirement contributions first, you reduce your overall taxable income before distributions come into play.

Step 4: Layer in Roth conversions. In lower-income years, consider converting traditional Solo 401(k) balances to Roth. Pay the tax now at a lower rate and enjoy tax-free growth going forward.

For a full walkthrough of this strategy, see our S-Corp Retirement Planning Guide.

Common Mistakes to Avoid

Missing the Solo 401(k) setup deadline. The plan must be established by December 31 of the tax year. You can make contributions until your tax filing deadline, but the plan document has to be in place by year-end. Don’t wait until April.

Defaulting to a SEP IRA without comparing. CPAs and financial advisors often recommend SEP IRAs because they’re easier to explain. But for most self-employed individuals earning over $60,000, the Solo 401(k) provides significantly more contribution capacity.

Ignoring the Roth option. If you’re under 50 and expect your income (and tax rates) to rise, putting at least some contributions into the Roth bucket of a Solo 401(k) can save substantial taxes over your lifetime.

Forgetting about the SIMPLE IRA October 1 deadline. If you’re considering a SIMPLE IRA, you must establish it by October 1. There’s no extension. This catches business owners off guard every year.

Not coordinating with S-Corp reasonable compensation. Your employer retirement contribution is based on your W-2 salary. If your salary is set too low, you’re capping your employer contribution unnecessarily. If it’s too high, you’re overpaying FICA. These two decisions need to be made together.

Frequently Asked Questions

Can I have both a SEP IRA and a Solo 401(k)?

Technically, yes, but it’s rarely beneficial. If you contribute to both, your total annual limit across both plans is still $72,000 (2026). And employee deferrals to the Solo 401(k) reduce dollar-for-dollar how much you can contribute to the SEP. Most people are better off consolidating into one plan.

What happens if I hire employees after setting up a Solo 401(k)?

The Solo 401(k) only covers the business owner (and spouse). If you hire common-law employees, you’ll need to either convert to a traditional 401(k) that covers all eligible employees or maintain a separate plan for them (like a SIMPLE IRA or SEP IRA). Plan for this before hiring.

Can my spouse participate in my Solo 401(k)?

Yes, if your spouse is a legitimate employee of your business and receives W-2 compensation. They can make their own $24,500 employee deferral, and you can make employer contributions on their behalf. This effectively doubles the household’s contribution capacity to $144,000+ annually.

Is a SEP IRA better for an LLC or an S-Corp?

For an LLC taxed as a sole proprietorship, it depends on your income and whether you need Roth access. For an S-Corp, the Solo 401(k) is almost always better because it allows employee deferrals on top of employer contributions based on your W-2 wages. S-Corp owners also get the added benefit of employer contributions being a deductible business expense.

When should I consider a Cash Balance Plan instead?

Cash Balance Plans make sense when you’re consistently earning over $300,000, are 45 or older, and want to shelter $100,000-$300,000+ beyond what a Solo 401(k) allows. They require actuarial administration ($2,000-$4,000/year) and mandatory annual contributions, so they’re best for stable, high-income practices. See our retirement tax planning overview for more on layered strategies.

What’s the deadline to make contributions for the current tax year?

For SEP IRAs: your tax filing deadline, including extensions (typically October 15 for calendar-year filers). For Solo 401(k) employee deferrals: December 31 of the tax year. For Solo 401(k) employer contributions: your tax filing deadline, including extensions. For SIMPLE IRAs: employee deferrals must be deposited within 30 days of the pay period.

Do Solo 401(k) contributions reduce self-employment tax?

Employee deferrals (the $24,500) do not reduce self-employment tax for sole proprietors. They reduce income tax only. However, for S-Corp owners, the employee deferral reduces W-2 wages for income tax purposes, and the employer contribution is a deductible business expense that’s exempt from FICA entirely.

Can I convert my SEP IRA to a Solo 401(k)?

You can roll over your SEP IRA balance into a Solo 401(k). This is a non-taxable event (assuming it’s a traditional-to-traditional rollover). Many self-employed individuals do this to consolidate accounts and gain access to Roth conversions or plan loans. Consult your plan custodian for the transfer process.

Next Steps

Picking the right plan is the first decision. The second is structuring your contributions, entity, and compensation to get the most from it.

If you’re earning over $100,000 as a self-employed individual and haven’t compared a Solo 401(k) to your current setup, you’re likely leaving money on the table. And if you’re already an S-Corp owner, coordinating your reasonable compensation with retirement contributions is one of the biggest tax savings available.

For more on the broader picture of self-employed taxation, start with our Self-Employed Tax Guide.

Want help picking the right retirement plan for your business? Get started with SDO CPA.