| Feature | Current rule |
|---|---|
| Income limit | None, unlike a Roth IRA |
| Employee deferral | Can be designated Roth, tax-deferred, or split between the two |
| Employer profit-sharing | Can be Roth or tax-deferred |
| In-plan conversions | Move a tax-deferred balance to Roth status; taxable in the year converted |
| Required Minimum Distributions | Do not apply to Solo 401(k) Roth funds |
| Roth IRA rollover in | Not permitted; a Roth IRA cannot roll into a Solo 401(k) |
Solo 401(k) contribution limits
What is a Roth Solo 401(k)?
A Roth Solo 401(k) is simply a standard Solo 401(k) with the Roth feature turned on, not a separate type of plan. Within a single plan, you may hold both tax-deferred and Roth participant accounts, and you can build a balance in either or both as your situation evolves.
Are there income limits on Roth Solo 401(k) contributions?
No. While the ability to contribute to a Roth IRA phases out and disappears entirely above certain income levels; the Roth Solo 401(k) carries no such restriction. If you qualify for a Solo 401(k) in the first place, meaning self-employment income and no full-time common-law employees, you can make Roth contributions regardless of how much you earn. That makes the Roth Solo 401(k) a powerful alternative for high earners who are locked out of a Roth IRA.
How much can I contribute, and how is it split between the two account types?
Your employee deferral can be made tax-deferred, Roth, or a combination of the two. Employer profit-sharing contributions can be made on either a Roth basis or tax-deferred, a result of SECURE 2.0.
Note: High earners electing to make catch-up contributions may be required to make those on a Roth basis.
How are the tax-deferred and Roth portions tracked?
The two portions are tracked as separate participant accounts within the same plan. Maintaining a dedicated bank account for each is standard practice and keeps plan recordkeeping clean. You need to be able to document the value of each account separately at all times.
Can I convert existing funds to Roth status inside the plan?
Yes, through an in-plan Roth rollover. You move value from the tax-deferred participant account to the Roth participant account, document the transaction in your plan records, and issue yourself a Form 1099-R reporting the converted amount as ordinary income for that year.
What is the Mega Backdoor Roth, and does it apply here?
The Solo 401(k) also supports after-tax contributions that can be converted to Roth status inside the plan, a technique commonly called the Mega backdoor Roth. For self-employed individuals with earnings between the deferral limit and the amount required to fully contribute to the plan maximum, It provides the opportunity to route significantly more money into Roth status. After-tax contributions can be used to fill the gap between combined deferrals plus employer contributions and the plan limit.
What counts as a qualified distribution from a Roth Solo 401(k)?
A qualified distribution from the Roth side of your plan comes out entirely free of tax and penalty. Two conditions have to be met at the same time: the Roth account must have been open and funded for at least five tax years, and a qualifying event has to apply, such as reaching age 59 1/2, permanent disability, or death. If either condition isn't met, a distribution of earnings can be taxed as ordinary income and hit with the 10 percent early withdrawal penalty. Plan Roth contributions aren't subject to that treatment, and can be distributed tax-free.
Are Roth Solo 401(k) funds subject to Required Minimum Distributions?
No. Roth accounts within a Solo 401(k) are not subject to Required Minimum Distributions during the original account holder's lifetime. That exemption covers only the Roth side of your plan, though; any balance still sitting in the tax-deferred account remains subject to the standard Solo 401(k) distribution rules, including Required Minimum Distributions, until it's converted or distributed.
Frequently Asked Questions
Can I have both a tax-deferred and a Roth balance in the same Solo 401(k)?
Yes. They're tracked as two separate participant accounts inside one plan, and you can build a balance in either or both depending on how you allocate contributions over time.
Can I roll my existing Roth IRA into my Roth Solo 401(k)?
No. A Roth IRA cannot be rolled into a Solo 401(k) under current rules. Roth funds from a prior employer's Roth 401(k) or 403(b) can be rolled in directly, but a Roth IRA is a one-way street once it exists.
Sam turns 61 this year. Which catch-up limit applies to Sam's contributions?
The higher catch-up range for ages 60 through 63 applies instead of the standard age-50 catch-up amount. Once Sam turns 64, the standard catch-up amount applies again.
Does converting my tax-deferred balance to Roth status remove my Required Minimum Distribution exposure for that year?
Not right away. Your Required Minimum Distribution for the year of the conversion is based on your plan's tax-deferred balance as of the end of the prior year, before the conversion took place, so converting during the year doesn't erase that year's requirement. In later years, once no tax-deferred balance remains in the plan, there's no Required Minimum Distribution left to satisfy.
Does the Mega Backdoor Roth work the same way in every Solo 401(k) plan?
No. It depends on whether the plan document allows after-tax, non-Roth contributions, something many providers choose to leave out because it adds administrative complexity they'd rather avoid. The Self-Directed Plans Solo 401(k) plan document supports it.
Should I talk to a professional before enabling Roth contributions in my plan?
Yes. A CPA or your plan provider can help confirm how these rules apply to your specific income and contribution history.