Solo 401(k) vs SEP IRA: Key Differences and Considerations

By Rebecca Lake · February 01, 2022 · 6 minute read

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Solo 401(k) vs SEP IRA: Key Differences and Considerations

Self-employment has its perks but an employer-sponsored retirement plan isn’t one of them. Opening a solo 401(k) or a Simplified Employee Pension Individual Retirement Account (SEP IRA) allows the self-employed to build wealth for retirement while enjoying some tax advantages.

A solo 401(k) or one-participant 401(k) is similar to a traditional 401(k), in terms of annual contribution limits and tax treatment. A SEP IRA, meanwhile, follows the same tax rules as traditional IRAs. SEP IRAs, however, allow a higher annual contribution limit than a regular IRA.

So, which is better for you? The answer can depend largely on whether your business has employees or operates as a sole proprietorship and which plan yields more benefits, in terms of contribution limits and tax breaks.

Weighing the features of a solo 401(k) vs. SEP IRA can make it easier to decide which one is more suited to your retirement savings needs.

Investing for Your Retirement When Self-Employed

An important part of planning for your retirement is understanding your long-term goals. Whether you choose to open a solo 401(k) or make SEP IRA contributions can depend on how much you need and want to save for retirement and what kind of tax advantages you hope to enjoy along the way.

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A solo 401(k) could allow you to save more for retirement on a tax-advantaged basis compared to a SEP IRA, but not everyone can contribute to one. It’s also important to consider whether you need to give some thought to retirement planning for employees.

If you’re hoping to mirror or replicate the traditional 401(k) plan experience, then you might lean toward a solo 401(k). Whether you can contribute to one of these plans depends on your business structure. Business owners with no employees or whose only employee is their spouse can use a solo 401(k).

Meanwhile, you can establish a SEP IRA for yourself as the owner of a business as well as your eligible employees, if you have any. It’s also helpful to think about what kind of investment options you might prefer. What you can invest in through a solo 401(k) plan may be different from what a SEP IRA offers, which can affect how you grow wealth for retirement.

Solo 401(k) vs SEP IRA Comparisons

Both solo 401(k) plans and SEP IRAs make it possible to save for retirement as a self-employed person or business owner when you don’t have access to an employer’s 401(k). You can set up either type of account if you operate as a sole proprietorship and have no employees. And both can offer a tax break if you’re able to deduct contributions each year.

In terms of differences, there are some things that set solo 401(k) plans apart from SEP IRAs. Under SEP IRA rules, for instance, neither employee nor catch-up contributions are allowed. There’s no Roth option with a SEP IRA, which you may have with a solo 401(k). Choosing a Roth solo 401(k) might appeal to you if you’d like to be able to make tax-free withdrawals in retirement.

You may also be able to take a loan from a solo 401(k) if the plan permits it. Solo 401(k) loans follow the same rules as traditional 401(k) loans. If you need to take money from a SEP IRA before age 59 ½, however, you may pay an early withdrawal penalty and owe income tax on the withdrawal.

Here’s a rundown of the main differences between a 401(k) vs. SEP IRA.

Solo 401(k)

SEP IRA

Tax-Deductible Contributions Yes, for traditional solo 401(k) plans Yes
Employer Contributions Allowed Yes Yes
Employee Contributions Allowed Yes Yes
Withdrawals Taxed in Retirement Yes, for traditional solo 401(k) plans Yes
Roth Contributions Allowed Yes No
Catch-Up Contributions Allowed Yes No
Loans Allowed Yes No

What Is a Solo 401(k)?

A solo 401(k) or one-participant 401(k) plan is a traditional 401(k) that covers a business owner who has no employees or employs only their spouse. Simply, a Solo 401(k) allows you to save money for retirement from your self-employment or business income on a tax-advantaged basis.

These plans follow the same IRS rules and requirements as any other 401(k). There are specific solo 401(k) contribution limits to follow, along with rules regarding withdrawals and taxation. Regulations also govern when you can take a loan from a solo 401(k) plan.

A number of online brokerages now offer solo 401(k) plans for self-employed individuals, including those who freelance or perform gig work. You can open a retirement account online and start investing, no employer other than yourself needed.

If you use a solo 401(k) to save for retirement, you’ll also need to follow some reporting requirements. Generally, the IRS requires solo 401(k) plan owners to file a Form 5500-EZ if it has $250,000 or more in assets at the end of the year.

Solo 401(k) Contribution Limits

Just like other 401(k) plans, solo 401(k)s have annual contribution limits. You can make contributions as both an employee and an employer. Here’s how annual solo 401(k) contribution limits work for elective deferrals:

Solo 401(k) Contribution Limits by Age in 2021 (Elective Deferrals)

Annual contribution in 2022

Annual Contribution Catch-Up Contribution in 2021 and 2022
Under 50 $19,500 N/a $20,500
50 and Older $19,500 $6,500 $20,500

The limit on 401(k) contributions, including elective deferrals and employer nonelective contributions, is $58,000 for 2021 and $61,000 in 2022. That doesn’t include an additional $6,500 allowed for catch-up contributions if you’re 50 or older.

If you’re self-employed, the IRS requires you to make a special calculation to figure out the maximum amount of elective deferrals and employer nonelective contributions you can make for yourself. This calculation reflects on your earned income, or means your net earnings from self-employment after deducting one-half of your self-employment tax and contributions for yourself.

The IRS offers a rate table you can use to calculate your contributions. You can set up automatic deferrals to a solo 401(k), or make contributions at any point throughout the year.

What Is a SEP IRA?

A SEP IRA or Simplified Employee Pension Plan is another option to consider if you’re looking for retirement plans for those self-employed. This tax-advantaged plan is available to any size business, including sole proprietorships with no employees, and its one of the easiest retirement plan to set up and maintain. So if you’re a freelancer or a gig worker, you might consider using a SEP IRA to plan for retirement.

SEP IRAs work much like traditional IRAs, with regard to the tax treatment of withdrawals. They do, however, allow you to contribute more money toward retirement each year above the standard traditional IRA contribution limit. That means you could enjoy a bigger tax break when it’s time to deduct contributions.

If you have employees, you can make retirement plan contributions to a SEP IRA on their behalf. SEP IRA contribution limits are, for the most part, the same for both employers and employees. If you’re interested in a SEP, you can set up an IRA for yourself or for yourself and your employees through an online brokerage.

SEP IRA Contributions

SEP IRA contributions use pre-tax dollars. Amounts contributed are tax-deductible in the year you make them. All contributions are made by the employer only, which is something to remember if you have employees. Unlike a traditional 401(k) that allows elective deferrals, your employees wouldn’t be able to add money to their SEP IRA through paycheck deductions.

Here’s how SEP IRA contributions work.

SEP IRA Contributions by Age

Annual Contribution Catch-Up Contribution
Under 50 Lesser of 25% of the employee’s compensation or $58,000 in 2021 and $61,000 in 2022. N/a
50 and Older Lesser of 25% of the employee’s compensation or $58,000 and $61,000 in 2022. N/a

The IRS doesn’t allow catch-up contributions to a SEP IRA, a significant difference from solo 401(k) plans. So it’s possible you could potentially save more for retirement with a solo 401(k), depending on your age and earnings. If you’re self-employed, you’ll need to follow the same IRS rules for figuring your annual contributions that apply to solo 401(k) plans.

You can make SEP IRA contributions at any time until your taxes are due, in mid-April of the following year.

The Takeaway

Saving for retirement is something that you can’t afford to put off. Whether you choose a solo 401(k), SEP IRA or another savings plan, it’s important to take the first step toward growing wealth.

If you’re ready to start saving for the future, one way to get started is by opening a brokerage account on the SoFi Invest investment platform. All members get complimentary access to a financial advisor, which can help you create a plan to meet your long-term goals.

Photo credit: iStock/1001Love


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