What exactly is the mandatory Roth catch-up rule?

Under SECURE Act 2.0, Section 603 (IRC § 414(v)(7)(C)), employees who are age 50 or older AND earned $150,000 or more in FICA wages from the employer sponsoring their plan in the prior tax year must designate ALL catch-up contributions as Roth (after-tax). This means you pay tax on the contribution now but owe no tax on the growth or withdrawal in retirement. The rule is effective January 1, 2026. It applies to 401(k), 403(b), and governmental 457(b) plans.

How do I know if my FICA wages meet the $150,000 threshold?

Look at Box 3 of your most recent W-2 from the employer that sponsors your retirement plan. Box 3 is labeled "Social Security wages" and represents your FICA-taxable compensation. This is often different from your total gross pay (Box 1) because it excludes items like pre-tax health insurance premiums, FSA contributions, and certain deferred compensation. If your W-2 Box 3 shows $150,000 or more, you are above the threshold for the following year.

What happens if my plan does not offer a designated Roth account?

If your plan lacks a Roth 401(k) option, you cannot make any catch-up contributions at all — the rule does not allow using the pre-tax option as a workaround for high earners. This means losing up to $8,000 (or $11,250 if age 60–63) in annual retirement savings capacity. Contact your HR department immediately to request that the plan add a designated Roth option. Most major recordkeepers (Fidelity, Vanguard, Schwab, Empower) can enable this quickly.

Does the mandatory Roth rule apply to 403(b) and 457(b) plans?

Yes. The mandatory Roth catch-up rule applies to 401(k), 403(b), and governmental 457(b) plans. It does NOT apply to SIMPLE IRAs, SEP IRAs, or non-governmental 457(b) plans. For governmental 457(b) plans, the threshold is measured separately per employer.

What is the "super catch-up" for ages 60–63?

SECURE Act 2.0 introduced a higher catch-up contribution limit for participants who turn 60, 61, 62, or 63 during the calendar year. For 2026, this is $11,250 versus the standard $8,000 — an extra $3,250 per year. If you're also subject to the mandatory Roth rule (FICA ≥ $150K), the entire $11,250 must go to Roth. The super catch-up window ends the moment you turn 64, when you revert to the standard $8,000 limit.

How does forced Roth affect my taxes this year?

The catch-up contribution previously reduced your taxable income by the catch-up amount (e.g., $8,000 at 24% federal rate saved $1,920 in federal tax). Under the mandatory Roth rule, the catch-up no longer reduces your taxable income — you owe that $1,920 (plus state tax) this year. You should increase your W-4 federal withholding to avoid underpayment penalties, or make an estimated tax payment. Use the calculator above to find the recommended monthly withholding adjustment.

Should I adjust my W-4 because of this rule?

Yes. If you previously relied on the pre-tax catch-up to reduce your withholding or to eliminate an underpayment, the Roth catch-up will leave you owing more at filing. The recommended adjustment is to add the extra annual federal tax ÷ 12 to the additional withholding field on your W-4 (Step 4c). The calculator shows this amount. You can update your W-4 at any time via your payroll system — it is not limited to open enrollment.

Can I still make pre-tax contributions up to the base $24,500 limit?

Yes. The mandatory Roth rule applies only to the catch-up portion (above the base $24,500 limit). You can direct your regular $24,500 to pre-tax or Roth or a combination — that choice remains yours. Only the additional catch-up dollars ($8,000 or $11,250) must go to Roth if you are affected.

Is Roth actually better or worse than pre-tax in the long run?

It depends entirely on whether your tax rate is higher now or in retirement. If your retirement marginal rate is lower than your current rate (the more common scenario for high earners who will have less income after leaving work), pre-tax would have been better — the forced Roth costs you more in the long run. If your retirement rate stays the same or rises (large RMDs, pension, rental income, Social Security), Roth wins. The break-even retirement rate equals your current combined federal + state rate.

What if I work for two employers — which wages count?

The threshold test is per employer and per plan. Only FICA wages from the employer sponsoring the plan you are contributing to count. If your primary employer (where your 401k is) paid you $130,000 and you also have a side job paying $30,000 (with a separate Solo 401k), only the $130,000 counts for the primary plan's test — you are below the threshold and not affected by that plan's mandatory Roth rule. Each plan is tested independently.

What is the penalty if my employer implements this incorrectly?

The plan itself becomes a disqualified plan if it fails to implement the mandatory Roth rule correctly, which can result in significant tax consequences for all participants. The IRS has provided transition relief, but plans are expected to be in full compliance as of January 1, 2026. If you believe your employer is not applying the rule correctly, document your FICA wages and notify your plan administrator in writing.

Does this rule affect my spouse's retirement plan separately?

Yes. Each person's eligibility is determined by their own FICA wages from their own employer. If your spouse earns $130,000 from their employer and you earn $200,000 from yours, you are affected but your spouse is not. Each plan is tested independently based on the sponsoring employer's payroll records.

I'm self-employed with a Solo 401(k) — does this apply to me?

Solo 401(k) plans are generally not subject to the mandatory Roth catch-up rule because you are both the employer and employee, and the FICA wage test is measured at the employer level. However, you are free to voluntarily designate your Solo 401k catch-up contributions as Roth — which may be beneficial if you expect to face higher taxes in retirement from Social Security, RMDs, or other income sources.

Retirement & Investing

Mandatory Roth Catch-Up Contribution Calculator

Find out if the new SECURE 2.0 rule forces your catch-up contributions to Roth, how much extra tax you owe this year, and whether Roth is better or worse long-term.

By The FinCalc TeamUpdated May 25, 2026

Starting January 1, 2026, a new SECURE Act 2.0 rule (IRC § 414(v)(7)(C)) requires that any employee age 50 or older who earned $150,000 or more in FICA wages from their employer in the prior year must make all catch-up contributions to a Roth (after-tax) account — not a traditional pre-tax account. There is no partial rule: the entire catch-up amount must go to Roth. If your plan does not offer a designated Roth option, you cannot make catch-up contributions at all. This calculator tells you whether you are affected, how much extra tax you will owe this year from losing the pre-tax deduction, and whether Roth is actually better or worse for you long-term based on your current and projected retirement tax rates.

How This Calculator Works

Eligibility Check

The calculator first determines whether you are subject to the mandatory Roth rule:

Affected = (FICA wages from sponsoring employer ≥ $150,000) AND (age ≥ 50 by Dec 31)

Age-based catch-up limits (2026):

| Age range | Catch-up type | Limit | |-----------|--------------|-------| | Under 50 | Not eligible | $0 | | 50–59 | Standard | $8,000 | | 60–63 | Super catch-up | $11,250 | | 64+ | Standard | $8,000 |

Current-Year Tax Impact

The pre-tax deduction you previously received is now lost on the catch-up portion:

Extra federal tax = catch-up amount × (current federal marginal rate)
Extra state tax   = catch-up amount × (state marginal rate)
Extra total tax   = extra federal tax + extra state tax

Recommended monthly W-4 increase = extra federal tax ÷ 12

Long-Term Roth vs. Pre-Tax Comparison

Both routes start with the same catch-up capacity but generate different after-tax outcomes:

Roth route (mandatory for affected participants):

Today: you pay tax on the catch-up contribution
At retirement: withdraw tax-free

After-tax value at retirement = catch-up × (1 − current total rate) × (1 + r)^years

Pre-tax route (hypothetical — what would have happened before the rule):

Today: contribution reduces taxable income (saves tax now)
At retirement: withdrawal is taxed at retirement marginal rate

After-tax value at retirement = catch-up × (1 + r)^years × (1 − retirement total rate)

Break-even: The two routes produce equal after-tax wealth when your retirement total tax rate equals your current total tax rate. Above that rate, Roth wins; below it, pre-tax would have been better.

Projection Chart

The chart shows the after-tax equivalent value of your catch-up contribution at each year between now and retirement. Both lines grow at the same rate (your investment return assumption). The Roth line starts lower (you paid more tax today) or higher (you avoid more tax tomorrow), depending on the rate comparison.

When to Use This Calculator

1. Open Enrollment: Deciding How to Direct Your 401(k) Contributions

During open enrollment, confirm whether your W-2 Box 3 wages exceed $150,000 and update your deferral elections accordingly. Your payroll system must now route your catch-up elections to the designated Roth account if you are affected. If your plan's enrollment system still shows pre-tax as an option for catch-up — and you are affected — flag this to your HR department.

2. W-4 Withholding Adjustment

If you previously relied on pre-tax catch-up contributions to reduce your withholding, you now owe more in taxes on those dollars. Use this calculator to find the recommended monthly withholding increase (shown as the W-4 adjustment amount), then update your W-4 via your payroll portal. You can do this at any time of year.

3. Comparing Roth vs. Pre-Tax for the Base Contribution

Even though the catch-up is mandatory Roth, your base $24,500 contribution is still your choice. If the calculator shows that Roth wins at your rate combination, consider also directing your base contribution to Roth — diversifying your retirement tax treatment.

4. Year-End Tax Planning

Use the calculator in November–December to confirm your year's catch-up total and the associated extra tax. If you contributed your full catch-up but did not adjust your withholding, you may owe a balance-due at filing. Running the estimate now lets you make a Q4 estimated payment to avoid underpayment penalties (IRC § 6654).

Understanding the Inputs

Prior Year FICA Wages (W-2 Box 3): The key trigger for this rule is FICA wages — specifically, the amount in Box 3 of your W-2 labeled "Social Security wages," not your total compensation or adjusted gross income. If you earned $150,000 or more from the employer that sponsors your retirement plan in the prior year, the rule applies to your catch-up contributions in the current year. If you have two W-2 employers and only one sponsors your 401(k), only that employer's wages count toward the threshold.
Your Age (by Dec 31, 2026): Your age as of December 31 determines which catch-up limit applies. The standard catch-up is $8,000 (age 50–59 and 64+). The "super catch-up" of $11,250 applies to ages 60, 61, 62, and 63 only — the moment you turn 64, you revert to the standard $8,000 limit. This four-year window is one of the most valuable retirement savings opportunities in the tax code and should be fully utilized if possible.
Catch-Up Contribution Amount: The dollar amount of catch-up contributions you intend to make beyond the $24,500 base 401(k) limit. The maximum is $8,000 (standard) or $11,250 (super catch-up for ages 60–63). If you contribute the full catch-up and are affected by the mandatory Roth rule, the entire catch-up amount must be designated as Roth. You can still direct your base $24,500 to pre-tax as desired.
Does Your Plan Offer a Roth Account?: If your employer's retirement plan does not include a designated Roth 401(k) or Roth 403(b) option, you face a serious problem: you cannot make catch-up contributions at all — not as pre-tax and not as Roth. The rule does not allow high-earners to use the old pre-tax catch-up as a workaround. If your plan lacks a Roth option, contact your HR department immediately to request plan adoption. Many recordkeepers (Fidelity, Vanguard, Schwab) offer Roth 401(k) as a standard feature.
Current Federal Marginal Rate: Your 2026 marginal federal income tax rate — the rate that applies to your last dollar of income. Common rates for employees subject to this rule (earning $150K+): 22% (single $103K–$197K, married $206K–$394K), 24% (single $197K–$250K, married $394K–$501K), 32% (single $250K–$626K). Use your top bracket rate, not your effective rate.
State Income Tax Rate: Your state marginal income tax rate. This applies both to the current-year cost (the deduction you're losing) and is assumed constant at retirement for the long-term comparison. If you plan to move to a no-tax state in retirement (TX, FL, NV, WA, etc.), your retirement rate will be lower and pre-tax contributions would have been more valuable. Enter 0 if you live in a state with no income tax.
Projected Retirement Federal Rate: The federal marginal rate you expect to face when withdrawing from your retirement account. This is the key variable that determines whether the forced Roth treatment helps or hurts you long-term. If you expect to be in a lower bracket in retirement (common for many high-earners who lose employment income), pre-tax would have been better. If you expect to stay in a high bracket (rental income, large RMDs, Social Security, pension), Roth wins.
Expected Investment Return: The annual nominal return expected inside the retirement account. This applies equally to both routes since the money grows in the same account. A higher return amplifies the long-term difference between Roth and pre-tax: at 10% annual return over 20 years, any tax-rate difference matters a lot more than at 5% over 5 years. Historical 60/40 portfolio return: roughly 7–8% nominal.
Years to Retirement: How many years until you plan to retire and begin taking distributions. The longer the horizon, the larger the difference between Roth and pre-tax outcomes — because tax-free growth compounds for more years. Shorter horizons make the current-year tax cost more painful relative to the long-term benefit.

Frequently Asked Questions

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The FinCalc Team

Personal Finance Experts

The FinCalc team is a group of personal finance writers, analysts, and engineers dedicated to building accurate, transparent financial calculators. Every formula is verified against industry standards and explained in plain language.

Last reviewed and updated: May 25, 2026