You can open a Roth 401(k) without an employer by setting up a Solo 401(k), also called a one-participant 401(k), as long as you have legitimate self-employment income. The plan itself has to be adopted by December 31 of the tax year you want to contribute for, and for 2026 you can put up to $24,500 of after-tax Roth dollars into the employee deferral bucket, with more room if you’re 50 or older. If you only earn W-2 wages and have no self-employment activity, this path isn’t available to you — your retirement options are limited to whatever your employer offers.
Who Qualifies
The eligibility rule is simple: you need earned income from self-employment. That can come from a sole proprietorship, a partnership, an S corporation, or a C corporation. The business structure doesn’t matter as long as you’re an owner generating earned income.1Fidelity. Understanding the Self-Employed 401(k) Freelancers, independent consultants, and side-business owners all qualify, even if they also hold a separate W-2 job.
The one restriction that trips people up involves employees. A Solo 401(k) can only cover the business owner and, if applicable, a spouse who works for the business. Once you hire anyone else who works 1,000 or more hours per year, you no longer qualify for the solo version and must convert to a standard employer-sponsored plan.1Fidelity. Understanding the Self-Employed 401(k) Part-time or seasonal help under that threshold generally won’t disqualify you, but track hours carefully.
Starting a side business only to open a Solo 401(k) is technically permissible, but the business has to generate real income. The IRS won’t recognize a shell operation with no actual economic activity.
What Income Counts
Not everything on your tax return is usable here. Rental income, dividends, interest, and capital gains are passive and cannot support Solo 401(k) contributions. What the IRS calls earned income for the self-employed is your net earnings from self-employment after deducting half of your self-employment tax and your own plan contributions.2Internal Revenue Service. One-Participant 401(k) Plans The circular-sounding calculation is worked out through worksheets in IRS Publication 560.
The type of income document you receive is a good tell. A 1099-NEC from a client or a Schedule K-1 from a partnership reflects self-employment income. If you own an S corporation, your W-2 wages from the business count as compensation for plan purposes. In every case, your total contributions for the year cannot exceed your actual earned income. You can’t put in $24,500 if the business netted $15,000.
How to Set the Plan Up
Get an Employer Identification Number
Every Solo 401(k) needs its own EIN from the IRS, even if you already use your Social Security number for business tax filings. The retirement plan is treated as a separate entity for reporting purposes.3Internal Revenue Service. Get an Employer Identification Number Applying online is immediate.
Adopt the Plan Document
The legal foundation of the plan is a Plan Adoption Agreement. It spells out who participates, how contributions work, and whether the plan offers a Roth option. Most brokerages that support Solo 401(k) plans provide a pre-approved template. You fill in the business name, the plan’s effective date, and the designated trustee, which is typically you. Completing this document is what the IRS considers “establishing” the plan.
Choose a Brokerage That Supports Roth
Not every financial institution offers Solo 401(k) plans with a Roth component. Confirm that the brokerage you’re considering supports designated Roth contributions before you sign anything. Once you submit the adoption agreement and account application, digital submissions usually process within a few business days. Link a business bank account for ongoing contributions.
Watch the December 31 Deadline
This is the date that matters most. Your plan must be adopted by December 31 of the tax year you want to contribute for.4Internal Revenue Service. Publication 560 (2025), Retirement Plans for Small Business You don’t have to fund the account by then. You have until your tax filing deadline, including extensions, to move money in. But if the plan documents aren’t signed by New Year’s Eve, you lose the ability to make any contributions for that year. People discover Solo 401(k) plans every February and learn this the hard way.
2026 Contribution Limits
Contributions have two parts: an employee deferral and an employer profit-sharing contribution. Each has its own limit.
The employee deferral limit for 2026 is $24,500, all of which can be designated as Roth.5Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living (Notice 2025-67) Catch-up contributions add more room based on age:
- Age 50 or older: an additional $8,000, for a total deferral of $32,500.6Internal Revenue Service. Retirement Topics – 401(k) and Profit-Sharing Plan Contribution Limits
- Ages 60 through 63: a higher catch-up of $11,250 instead of $8,000, for a total deferral of $35,750. This enhanced catch-up was created by the SECURE 2.0 Act and must be permitted by the plan.5Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living (Notice 2025-67)
On top of the employee deferral, you can make an employer profit-sharing contribution. The maximum depends on business structure. S corporation owners can contribute up to 25% of their W-2 wages. Sole proprietors and single-member LLC owners are limited to 20% of net self-employment income, because the lower percentage accounts for the self-employment tax deduction built into the calculation.2Internal Revenue Service. One-Participant 401(k) Plans
The overall cap on all contributions combined is $72,000 for 2026, $80,000 with the standard catch-up, or $83,250 with the enhanced catch-up for ages 60 through 63.5Internal Revenue Service. 2026 Amounts Relating to Retirement Plans and IRAs, as Adjusted for Changes in Cost-of-Living (Notice 2025-67) Contributions must be made by your tax filing deadline, including extensions.
One note if you also participate in an employer 401(k) elsewhere: the employee deferral limit applies across all plans combined, not per plan. Exceeding it means the excess amount gets taxed twice, once in the year you contributed it and again when you eventually withdraw it, unless you distribute the excess plus earnings by April 15 of the following year.7Internal Revenue Service. Consequences to a Participant Who Makes Excess Deferrals to a 401(k) Plan
Roth for the Employer Portion Too
Before 2023, employer profit-sharing contributions could only go into a pre-tax account. The SECURE 2.0 Act changed that. Participants can now elect to have employer matching and non-elective contributions designated as Roth, meaning those dollars are taxed upfront and grow tax-free.8Office of the Law Revision Counsel. 26 USC 402A – Optional Treatment of Elective Deferrals as Roth Contributions For a Solo 401(k) owner, this means your entire contribution can potentially be Roth if your plan document allows it.
There’s a tradeoff. Roth employer contributions are included in your gross income for the year you make them, unlike traditional employer contributions that reduce taxable income. Bigger tax bill now in exchange for tax-free growth later. Plans must be amended to offer this option, and the amendment deadline has been extended to December 31, 2026.
Choosing Roth or Traditional Inside the Plan
A Solo 401(k) can hold both Roth and pre-tax contributions, and you can split your employee deferrals between them however you like. The decision comes down to when you’d rather pay taxes.
Roth makes the most sense when you’re in a relatively low tax bracket now, such as a business’s early years or a year when income dipped. You pay tax on the money going in, but every dollar of growth comes out tax-free in retirement. If you expect tax rates to be higher when you retire, either because your income will grow or because Congress raises rates, Roth locks in today’s rate.
Pre-tax contributions work better in a high-earning year when you want to reduce your current tax bill. The deduction is worth more when your marginal rate is steep. You’ll pay income tax on withdrawals in retirement, but if your retirement income is lower than your peak working years, you come out ahead.
Many Solo 401(k) owners split contributions, making Roth deferrals in lean years and pre-tax deferrals in strong ones. The flexibility to choose each year is one of the plan’s biggest advantages over a Roth IRA, which has income limits that can disqualify high earners entirely.
Withdrawal Rules to Know Before You Contribute
Roth 401(k) withdrawals are tax-free only if you’ve held the Roth account for at least five years and you’re at least 59½ (or disabled, or the distribution is made after death).9Internal Revenue Service. Roth Comparison Chart The five-year clock starts on January 1 of the year you make your first Roth contribution. Withdrawals that miss either condition trigger income tax on the earnings portion and a 10% early withdrawal penalty.
One useful change under the SECURE 2.0 Act: Roth 401(k) accounts are no longer subject to required minimum distributions during the original owner’s lifetime. Before this, Roth 401(k) holders had to start taking distributions at age 73, even though the money would come out tax-free. That requirement is gone, so the balance can keep growing untouched for as long as you live.
You can also roll a Roth 401(k) balance into a Roth IRA at any time after you leave self-employment or close the business.10Internal Revenue Service. Rollover Chart That gives you more flexibility with investments and avoids any plan-level restrictions. If you’ve already satisfied the five-year rule in the 401(k), the rolled-over funds remain qualified in the Roth IRA.
The $250,000 Reporting Threshold
Solo 401(k) plans with total assets of $250,000 or less at the end of the plan year don’t need to file anything with the IRS, which keeps the paperwork minimal in the early years.11Internal Revenue Service. Instructions for Form 5500-EZ Once the plan crosses that threshold, you must file Form 5500-EZ each year. You also need to file for the plan’s final year, regardless of balance.
Missing a required filing is expensive. The penalty is $250 per day for each late return, up to a maximum of $150,000 per filing.12Internal Revenue Service. Penalty Relief Program for Form 5500-EZ Late Filers The IRS offers a penalty relief program for late filers who come forward voluntarily, but filing on time is simpler. Check your year-end balance each December once you’re getting close.