How much can I contribute to a Roth 401(k)?
Last updated August 2026
Short answer
Three separate limits interact here, and mixing them up is what produces both under-contributing and the occasional excess deferral.
The 2026 figures
$24,500 in elective deferrals for anyone under 50.
From age 50, a catch-up of $8,000 takes it to $32,500. At ages 60, 61, 62 and 63, the catch-up is $11,250 instead, giving $35,750.
The higher band at 60 to 63 came from SECURE 2.0 and reverts to the ordinary catch-up from 64, which is a detail worth knowing if you are planning contributions across those years.
One limit across both sides
Roth and traditional deferrals share the ceiling. $15,000 Roth leaves $9,500 traditional in 2026.
Most plans allow the split to be changed during the year, so the mix can respond to how your income turns out.
Only your own deferrals count. Anything the employer puts in belongs to a different calculation.
The overall annual additions limit
Employee deferrals, employer match and any after-tax contributions together cannot exceed $72,000 in 2026, or 100% of compensation if lower.
This is the limit that makes the mega backdoor Roth possible in plans that permit after-tax contributions and in-plan conversions.
Most employees never approach it, which is why it goes unnoticed until somebody starts planning around it deliberately.
Try it in Walnut
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The Roth catch-up requirement
Under SECURE 2.0, catch-up contributions must be made on a Roth basis for employees whose prior-year wages from that employer exceeded a threshold.
The figure used for 2026 purposes is $150,000, up from $145,000, and it is indexed.
Plans implement this automatically, so the practical effect is that higher earners lose the deduction on the catch-up portion rather than losing the ability to make it.
Changing jobs, and excess deferrals
The deferral limit belongs to you rather than to each employer, so contributions at two employers in one year are added together.
Neither payroll department can see the other, so exceeding the limit is easy and entirely your responsibility to catch.
An excess deferral must be identified and returned by the deadline in April, otherwise it is taxed twice: once in the year contributed and again when distributed.
The mega backdoor route
Some plans allow after-tax contributions beyond the deferral limit, up to the $72,000 overall annual additions ceiling.
Where the plan also permits in-plan Roth conversion or in-service withdrawal, those after-tax dollars can be moved into Roth treatment.
Both features have to exist in your specific plan document, which is why this is common in some employers and impossible in most.
Sources
All 2026 figures are from IRS Notice 2025-67, including the $24,500 deferral limit, the $8,000 and $11,250 catch-ups, the $72,000 annual additions limit and the $150,000 Roth catch-up wage threshold. Walnut is informational and is not an investment adviser. This guide is educational and not personalized tax advice.
FAQ
How much can I contribute to a Roth 401(k) in 2026?
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$24,500 as an employee deferral, rising to $32,500 from age 50 with the $8,000 catch-up. At ages 60 to 63 the catch-up is $11,250 instead, taking the total to $35,750.
Does the employer match count against it?
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No. The employee deferral limit applies to your own contributions. Employer money counts toward the separate overall limit on annual additions, which is $72,000 in 2026.
Can high earners contribute?
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Yes, without restriction. Unlike a Roth IRA, which phases out between $153,000 and $168,000 for single filers in 2026, a Roth 401(k) has no income limit.
Do I have to make catch-up contributions Roth?
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From the applicable effective date, catch-up contributions must be made on a Roth basis for employees whose prior-year wages from that employer exceeded a threshold, which is $150,000 for 2026 purposes under Notice 2025-67. Plans handle this automatically.
Can I also contribute to a Roth IRA?
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Yes, if your income is within the IRA limits. The two are separate allowances, so a Roth 401(k) at $24,500 and a Roth IRA at $7,500 can both be funded in the same year.
What if I change jobs mid-year?
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The deferral limit is yours, not each employer's, so contributions across both plans count together. Two plans that each allow the full amount will happily let you exceed it, and correcting an excess deferral requires acting before the April deadline.
What is the mega backdoor Roth?
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Making after-tax contributions above the deferral limit, up to the $72,000 overall annual additions ceiling, then converting them to Roth inside the plan or rolling them to a Roth IRA. It requires the plan to permit both after-tax contributions and conversions, which most do not.
Does the annual additions limit include the catch-up?
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No. Catch-up contributions sit outside the $72,000 limit, so someone over 50 can effectively exceed it by the amount of their catch-up.
What happens if I contribute above the limit?
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The excess deferral has to be identified and returned by the deadline in April following the year it was made. Miss that and the money is taxed twice, once in the year contributed and again when it is eventually distributed, which is the worst outcome available in a retirement account.
Does the limit apply per employer or per person?
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Per person. The elective deferral limit is yours across every plan you participate in during the year, while the $72,000 annual additions limit is applied per employer. Someone with two unrelated employers can therefore receive employer contributions under two separate annual additions limits while still having only one deferral allowance.