S Corp Solo 401(k): $190,000 W-2 Maxes Pre-Tax, $72,000 Maxes Roth
Key takeaways: S Corp Solo 401(k) W-2 salary requirements for 2026
- The 2026 overall contribution limit for an S Corp Solo 401(k) is $72,000, combining employee, employer, and voluntary after-tax contributions.
- The 2026 employee deferral limit is $24,500 per person across all plans, so a maxed-out day-job 401(k) leaves no employee deferral room.
- The employer contribution is capped at 25% of S corporation W-2 wages, so $190,000 of W-2 wages supports a $47,500 employer contribution.
- An S Corp Solo 401(k) owner with no other plan needs $190,000 of W-2 wages for the $72,000 pre-tax maximum, or $288,000 if a day-job plan used the employee limit.
- A plan that allows voluntary after-tax contributions needs only $72,000 of W-2 wages to contribute $72,000, which can then be converted to Roth.
- The 2026 catch-up contribution is $8,000 for ages 50 to 59 and 64 and older, and $11,250 for ages 60 to 63, raising totals to $80,000 and $83,250.
- Form 1099-R reports the after-tax-to-Roth transfer, while the after-tax contribution itself does not appear on the W-2 or the tax returns.
Video: live My Solo 401k Financial webinar on the S Corp Solo 401(k) W-2 salary needed to max out 2026 contributions.
How much W-2 salary do I need to max out an S Corp Solo 401(k) in 2026?
An S Corp Solo 401(k) requires between $72,000 and $288,000 of 2026 W-2 wages to reach its maximum. The amount depends on the contribution type and on any day-job plan.
| Strategy | Total contribution | W-2 wages required | How the contribution splits |
|---|---|---|---|
| Pre-tax maximum, no other plan, under age 50 | $72,000 | $190,000 | $24,500 employee + $47,500 employer |
| Pre-tax maximum, no other plan, ages 50–59 or 64+ | $80,000 | $190,000 | $32,500 employee + $47,500 employer |
| Pre-tax maximum, no other plan, ages 60–63 | $83,250 | $190,000 | $35,750 employee + $47,500 employer |
| Pre-tax maximum, day-job plan already maxed | $72,000 | $288,000 | $72,000 employer only |
| Roth maximum, under age 50 | $72,000 | $72,000 | $72,000 after-tax, then converted to Roth |
| Roth maximum, ages 50–59 or 64+ | $80,000 | $80,000 | $72,000 after-tax + $8,000 catch-up straight to Roth |
| Roth maximum, ages 60–63 | $83,250 | $83,250 | $72,000 after-tax + $11,250 super catch-up straight to Roth |
What are the 2026 S Corp Solo 401(k) contribution limits?
The S Corp Solo 401(k) has three 2026 limits that work together: a $24,500 employee deferral limit, a 25% employer contribution limit, and a $72,000 overall limit.
Employee deferral limit: $24,500
The S Corp Solo 401(k) employee deferral limit for 2026 is $24,500, or 100% of W-2 wages when wages are lower. The limit belongs to the person, not the plan, so deferrals to a day-job 401(k) reduce the room left.
“… the employee contribution limit is $24,500. That’s 100% of your W-2 wages from your self-employed business taxed as an S corporation.”
Employer contribution limit: 25% of W-2 wages
The S Corp Solo 401(k) employer contribution limit is 25% of the owner’s W-2 wages from the S corporation. Wages for this purpose equal box one of the W-2 plus any pre-tax deferrals reported in box 12.
Overall limit and catch-up: $72,000 to $83,250
The S Corp Solo 401(k) overall limit for 2026 is $72,000, counting employee, employer, and voluntary after-tax contribution dollars together. Owners aged 50 to 59 or 64 and older at the end of 2026 can add an $8,000 catch-up contribution, for $80,000 in total. Owners aged 60 to 63 can add an $11,250 super catch-up instead, for $83,250 in total.
Each catch-up is available only when the owner has not used it in another plan, such as a day-job plan, and has the income to support it.
| Limit | 2026 amount | Where the limit applies |
|---|---|---|
| Employee deferral | $24,500 | Person level: shared across every plan the owner participates in |
| Catch-up, ages 50–59 and 64+ | $8,000 | Person level: unavailable if already used in another plan |
| Super catch-up, ages 60–63 | $11,250 | Person level: unavailable if already used in another plan |
| Employer contribution | 25% of W-2 wages | Plan level: based on W-2 wages from the S corporation |
| Overall limit | $72,000 | Plan level: a day-job 403(b) is aggregated with it |
What counts as W-2 income for an S Corp Solo 401(k)?
An S Corp Solo 401(k) counts only W-2 wages from the S corporation as income for contribution purposes. Schedule K-1 profit never counts, and no owner can save more than the wages earned.
“… your income when your business is taxed as an S corporation is really the W-2 wages that you receive from the S corporation. So it’s really box one of the W-2 plus any pre-tax elective deferrals not in box one but over in box 12.”
Wages reported in box one of the W-2 can be used to justify contributions. An owner who has already received W-2 wages does not need to run another payroll to justify contributions.
How much W-2 salary does an S Corp Solo 401(k) need for the pre-tax maximum with no day job?
An S Corp Solo 401(k) owner under age 50 with no other plan needs $190,000 of 2026 W-2 wages to contribute the full $72,000 pre-tax. The contribution splits into a $24,500 employee deferral and a $47,500 employer contribution.
“So, it’s box one plus box 12, that’s $190,000 times 25%. The employer contribution limit for an S corporation is 25% of the W-2 wages from the S corporation. So that yields 47,500, bringing their total contribution amount to $72,000.”
The S Corp Solo 401(k) employee deferral lowers box one of the W-2, which produces the income tax reduction. The $47,500 employer contribution is reported on the S corporation tax return and flows through the K-1 to the owner.
Ages 50 to 59 or 64 and older: $80,000
An S Corp Solo 401(k) owner aged 50 to 59 or 64 and older with $190,000 of W-2 wages and no other plan can contribute $80,000. The total is $32,500 of employee deferrals, which includes the $8,000 catch-up, plus the $47,500 employer contribution.
Ages 60 to 63: $83,250
An S Corp Solo 401(k) owner aged 60 to 63 at the end of 2026 can add the $11,250 super catch-up. Employee deferrals reach $35,750, and the $47,500 employer contribution brings the total to $83,250.
The $150,000 Roth catch-up rule
How much W-2 salary does an S Corp Solo 401(k) need if a day-job plan is already maxed out?
An S Corp Solo 401(k) owner who already maxed out a day-job 401(k) needs $288,000 of 2026 W-2 wages to make a $72,000 pre-tax contribution. The employee deferral limit applies to the person across all plans, so only the employer contribution remains.
The employer contribution is 25% of W-2 wages. A $72,000 employer contribution therefore requires $288,000 of W-2 wages.
“They would need $288,000 of W-2 wages from the business taxed as an S corp because 25% of $288,000 is $72,000, which again would be a pre-tax contribution to reduce their taxable income for 2026.”
How does the Mega Backdoor Roth work in an S Corp Solo 401(k)?
The Mega Backdoor Roth in an S Corp Solo 401(k) is a voluntary after-tax contribution followed by a transfer to the Roth account. For a deeper walkthrough, see this guide to the Mega Backdoor Roth using a Solo 401(k) plan.
The plan document must allow voluntary after-tax contributions. Discount brokerage plans do not allow them, while the My Solo 401k Financial plan does.
The S Corp Solo 401(k) process has two steps. First, the owner contributes to a separate after-tax account. Second, the owner moves the money to the Roth account, where it has potential for tax-free growth.
What gets reported
The after-tax contribution to an S Corp Solo 401(k) does not need to be reported on the personal return, the business return, or the W-2. The after-tax-to-Roth transfer is reportable on Form 1099-R. My Solo 401k Financial prepares that Form 1099-R at no additional charge when notified in a timely way through the form on its website.
Roth Solo 401(k) account or Roth IRA
Under the My Solo 401k Financial plan, after-tax money can move to either a Roth IRA or a Roth Solo 401(k). An owner who wants a Roth 401(k) loan option or alternative investments needs at least two accounts: an after-tax account and a Roth account. Learn more about the Solo 401(k) plan on the My Solo 401k Financial site.
How much W-2 salary does an S Corp Solo 401(k) need for the Roth maximum?
An S Corp Solo 401(k) owner can reach a $72,000 Roth balance with only $72,000 of W-2 wages. Voluntary after-tax contributions allow 100% of wages, dollar for dollar, up to the overall limit, so the owner can skip employee and employer contributions entirely.
“… as long as they have box one W-2 wages of $72,000, they can contribute the full $72,000 as an after tax contribution to the after tax solo 401k account and then convert the money to the Roth account.”
Day-job plans do not reduce the voluntary after-tax limit
The voluntary after-tax limit of an S Corp Solo 401(k) applies at the plan level, so a maxed-out day-job 401(k) does not reduce it. The owner still needs at least $72,000 of W-2 wages from the S corporation.
“… unlike the employee limit that applies at the employee level, the voluntary after tax contribution limit is not reduced by contributions made to a day job 401k plan. It applies at the plan level.”
There is an important exception. Contributions to a day-job 403(b), whether employee or employer, are aggregated with S Corp Solo 401(k) contributions, and the sum cannot exceed the overall limit.
Roth maximum with catch-up contributions
An S Corp Solo 401(k) owner aged 50 to 59 or 64 and older needs $80,000 of W-2 wages to add the $8,000 catch-up. An owner aged 60 to 63 needs $83,250 to add the $11,250 super catch-up. Catch-up dollars skip the after-tax bucket and go straight to Roth, so the owner ends with $80,000 or $83,250 in the Roth account.
Can an S Corp Solo 401(k) restated in October 2026 still receive 2026 mega backdoor Roth contributions?
An owner who restates a prior 401(k) into an S Corp Solo 401(k) in October 2026 can still make 2026 Mega Backdoor Roth contributions when unused overall-limit capacity remains.
“I’ve already contributed employee 401k and employer 401k contributions to my prior 401k plan. Can I restate with my solo 401k in October 2026 and still contribute after tax Mega Backdoor Roth for 2026?”
— Attendee question from G, submitted by chat and read aloud in the webinar by George Blower, Retirement Accounts Attorney, My Solo 401k Financial (21:22 in the webinar)
Contributions already made to the prior plan cannot be unwound, and they count against the limits. Any remaining capacity needs W-2 wages to justify it.
The after-tax contributions can be made by the business tax return deadline, including extensions. The 2026 S corporation deadline is , or with a timely extension. The plan must be established by the end of the year.
After the application and payment are submitted, My Solo 401k Financial prepares restatement documents within the same business day. Moving assets from the prior plan requires a separate transfer form.
S Corp Solo 401(k) W-2 salary FAQs
How much W-2 income do I need for the $72,000 pre-tax S Corp Solo 401(k) contribution?
An S Corp Solo 401(k) owner under age 50 with no other plan needs $190,000 of 2026 W-2 wages to contribute $72,000 pre-tax. The contribution splits into a $24,500 employee deferral and a $47,500 employer contribution, which equals 25% of $190,000. Box one of the W-2 falls to $165,500 because the deferral is reported in box 12.
How much W-2 salary do I need for an S Corp Solo 401(k) if I already max out a day-job 401(k)?
An S Corp Solo 401(k) owner who already maxed out a day-job 401(k) needs $288,000 of 2026 W-2 wages for a $72,000 pre-tax contribution. The employee deferral limit is shared across all plans, so only the employer contribution remains. Employer contributions equal 25% of W-2 wages, and 25% of $288,000 is $72,000.
Can I contribute $72,000 to a Solo 401(k) with only $72,000 of S corp W-2 wages?
Yes, if the S Corp Solo 401(k) plan document allows voluntary after-tax contributions. The owner contributes 100% of W-2 wages dollar for dollar up to $72,000 as voluntary after-tax money, then converts it to the Roth account. Discount brokerage plans do not allow voluntary after-tax contributions.
Does a day-job 401(k) reduce how much I can contribute after-tax to my S Corp Solo 401(k)?
A day-job 401(k) does not reduce the voluntary after-tax limit of an S Corp Solo 401(k). That limit applies at the plan level, not the person level. The exception is a day-job 403(b), whose employee and employer contributions are aggregated with S Corp Solo 401(k) contributions under the $72,000 overall limit.
Can I use K-1 profit to justify S Corp Solo 401(k) contributions?
No. An S Corp Solo 401(k) counts only W-2 wages from the S corporation as earned income. The base is box one of the W-2 plus any pre-tax elective deferrals reported in box 12. Schedule K-1 profit does not support contributions, and no owner can contribute more than the W-2 wages earned.
Is the Mega Backdoor Roth conversion in an S Corp Solo 401(k) reported to the IRS?
The transfer from the after-tax account to the Roth account in an S Corp Solo 401(k) is reportable on Form 1099-R. The after-tax contribution itself does not need to be reported on the personal return, the business return, or the W-2. Later transfers of like funds between bank and brokerage accounts are not reportable.
Can I restate to an S Corp Solo 401(k) in October 2026 and still make 2026 mega backdoor Roth contributions?
Yes, when overall-limit capacity remains. An S Corp Solo 401(k) restatement in October 2026 cannot unwind contributions already made to the prior plan. Remaining capacity can fund voluntary after-tax contributions if W-2 wages justify them. Those contributions are due by the business tax return deadline, including extensions.
Do S corp owners have to make Roth catch-up contributions to an S Corp Solo 401(k)?
An S Corp Solo 401(k) owner must make catch-up contributions as Roth when the S corporation paid more than $150,000 of Social Security wages in 2025. Below the threshold, the owner can choose Roth or pre-tax catch-up contributions. The 2026 catch-up is $8,000, or $11,250 for ages 60 to 63.
This article is based on the live webinar hosted by My Solo 401k Financial. Analysis by George Blower, Retirement Accounts Attorney, My Solo 401k Financial.
My Solo 401k Financial prepares plan documents that allow voluntary after-tax contributions and the Mega Backdoor Roth. Open a Solo 401(k) account with My Solo 401k Financial to get started.
