Mandatory Roth Catch-Up Calculator
Starting with 2026, if you’re 50 or older and earned more than $150,000 in Social Security (Box 3) wages last year from the employer that sponsors your plan, your 401(k) catch-up can no longer go in pre-tax — it must go in as Roth (after-tax). This is the SECURE 2.0 Act §603 rule. Enter your details to see whether it hits you, what the forced-Roth treatment costs this year, and whether that cost is actually a loss. Everything runs in your browser — nothing is uploaded.
Estimate for general guidance only — not tax or investment advice. The forced-Roth cost uses the marginal rate you pick; the future-value comparison is a simplified Roth-vs-pre-tax model (it doesn’t model state tax, RMDs, or IRMAA). For 2026 the mandate is in force under a “reasonable, good-faith” standard; strict compliance with the final regulations applies from 2027, and many collectively bargained and governmental plans have later start dates. Verify with your plan administrator or a tax professional.
Do I lose my catch-up? No — the 2026 Roth rule only changes how it’s taxed
What people fear: “I make over $150k, so in 2026 I can’t do my 401(k) catch-up anymore” — or “this is a new tax on high earners.”
What’s actually true: You keep every dollar of catch-up room — the full $8,000 (or $11,250 at ages 60–63). Nothing about the amount changes. The only change is that the catch-up now goes in as Roth (after-tax) instead of pre-tax: you don’t get the upfront deduction on it, but the money then grows and comes out completely tax-free in retirement. It’s a change in the timing of tax, not a new tax and not a lost benefit.
How the mandatory Roth catch-up rule works
The SECURE 2.0 Act of 2022 added §603, now written into law as Internal Revenue Code §414(v)(7), with final regulations at 26 CFR 1.414(v)-2. It applies to 401(k), 403(b), and governmental 457(b) plans and the federal Thrift Savings Plan. (SEP and SIMPLE IRA plans are excluded.)
Three gates, all must be true. The rule catches you only if: (1) you’re 50 or older by year-end, (2) your prior-year Social Security (Box 3) wages exceeded $150,000 from the employer that sponsors the plan, and (3) the plan offers Roth. Miss any one and your catch-up can still be pre-tax.
It’s last year’s wages, from that employer. For 2026 contributions the test uses your 2025 Social Security wages — Box 3 of your W-2, which is a FICA wage figure — from the same employer whose plan you’re in. Not this year’s pay, not your total or household income, and not self-employment income. A brand-new employee with no prior-year wages from that employer isn’t subject. The test is “exceed”: exactly $150,000 is not over the line.
$145,000 vs $150,000. The statute’s base amount is $145,000; indexed for inflation, it first moved to $150,000 for 2026 (IRS Notice 2025-67). $150,000 is the number that matters for 2026 contributions.
The catch-up amounts don’t change. For 2026 the age-50+ catch-up is $8,000, and the “super” catch-up for the year you turn 60, 61, 62, or 63 is $11,250, reverting to $8,000 at 64. The mandate applies to whichever amount is yours — an over-threshold 62-year-old must Roth the full $11,250; an over-threshold 64-year-old must Roth $8,000. Your regular elective deferral (up to $24,500 in 2026) can still be pre-tax.
If your plan has no Roth option, it isn’t forced to add one — it can instead simply bar high earners from making catch-up contributions at all until it does. So in a no-Roth plan a subject participant’s catch-up capacity is $0, not “pre-tax allowed.”
Thinking about the tax side of retirement more broadly? If you’re 65+, check the senior bonus deduction calculator for the $6,000 “no tax on Social Security” deduction, and the 401(k) retirement calculator to project your balance.
A worked example: Priya, 61, earning $220,000
Priya turns 61 this year, contributes to her employer’s 401(k), and her 2025 W-2 Box 3 wages were $220,000. She’s in the 35% federal bracket now and expects to be in the 24% bracket in retirement, 8 years out. Here’s what the rule does for her:
- Is she subject? Yes — she’s over 50 and her prior-year Social Security wages ($220,000) exceed the $150,000 threshold, in a plan that offers Roth.
- Her catch-up band: at 61 she’s in the 60–63 “super” band, so her 2026 catch-up maximum is $11,250 — unchanged by the rule.
- What changes: that $11,250 must go in as Roth, not pre-tax. She forgoes the upfront deduction: $11,250 × 35% = $3,937.50 in extra federal tax this year.
- Is that a real loss? Because she expects a lower 24% rate in retirement, paying 35% now is the worse side of the trade. At 6%/year over 8 years the Roth choice costs her roughly $1,970 in after-tax retirement value versus pre-tax — a genuine cost, though she still gets tax-free growth and no required minimum distributions in return.
- What it is NOT: she does not lose the $11,250 of catch-up room, and it isn’t a new tax — it’s the same money, taxed now instead of later.
Flip Priya’s expectation — if she thought her retirement rate would be higher than 35% — and the forced-Roth treatment would come out ahead. That’s the whole point of the break-even: the answer depends on your rates, not on a blanket “Roth is worse.”
Common questions
What is a catch-up contribution? An extra amount people 50 and older can add to a workplace plan on top of the normal annual limit — $8,000 for 2026 (or $11,250 at ages 60–63). The rule changes only how a high earner’s catch-up is taxed, not how much they can put in.
What does “Roth” mean here? A designated Roth contribution is made with after-tax dollars: no deduction the year you contribute, but qualified withdrawals of contributions and earnings are tax-free in retirement. Pre-tax (traditional) is the reverse — deductible now, taxed at withdrawal. This rule forces high earners’ catch-up into the Roth (after-tax) bucket.
Which wages count — Box 1, Box 3, or Box 5? Box 3, your Social Security (FICA) wages, from the employer that sponsors your plan. Not Box 1 (federal taxable wages) and not Box 5 (Medicare wages). Note that your pre-tax 401(k) deferrals are still included in Box 3, so contributing more pre-tax won’t pull you under the line.
Does it apply to a SEP or SIMPLE IRA? No. The rule covers 401(k), 403(b), governmental 457(b), and the federal TSP. SEP (§408(k)) and SIMPLE IRA (§408(p)) arrangements are excluded.
I’m self-employed — am I caught? If your only earnings are self-employment income (which is SECA, not FICA), you have no Box 3 wages from a plan sponsor, so there’s nothing to test — you’re not subject.
If my plan has no Roth option, am I forced to open one? No — but the plan can then bar you from catch-ups entirely until it adds Roth. Most large plans are adding a Roth option.
What is the marginal tax rate this uses? Your marginal tax rate is the rate on your next dollar of income. It sets how much the upfront deduction you forgo is worth, and it’s the break-even point for the Roth-vs-pre-tax comparison.
Is anything saved or uploaded? No. The tool is fully client-side — your numbers never leave your browser.
Sources: IRS Notice 2025-67 (2026 threshold $150,000; $24,500 deferral; $8,000 catch-up; $11,250 super catch-up; SEP/SIMPLE exclusion); IRS newsroom, 401(k) limit increases to $24,500 for 2026; final regulation 26 CFR 1.414(v)-2 (preceding-year §3121(a) FICA wages, $145,000 base, no-FICA-wages exemption, applicability after Dec 31, 2026); T.D. 10033 (good-faith relief for 2026, governmental/CBA dates); IRS Notice 2023-62 (transition period through 2025); statute IRC §414(v)(7) (SECURE 2.0 §603).