Do IRA and 401(k) withdrawals trigger IRMAA?

Yes. Traditional IRA and 401(k) withdrawals raise your Modified Adjusted Gross Income, which can push you into higher Medicare IRMAA tiers and raise your Part B and Part D premiums. Qualified Roth withdrawals are not counted in MAGI, so they do not trigger IRMAA.

Could future tax rates change the answer?

The 2017 tax rates were made permanent by the 2025 OBBBA, so there is no scheduled increase. But future Congresses could still raise rates given federal deficits. Because Roth withdrawals are tax-free regardless, a Roth conversion acts as insurance against higher future rates. The calculator lets you model an assumed rate increase.

Free tool · 2026 brackets

Roth Conversion Tax Calculator

Compare four paths for your retirement dollars — leave it in your IRA/401(k), convert and pay the tax, spread the conversion over several years, or convert with a deduction offset — across your whole retirement.

Your situation

Account balance

$

$50K$3M+

Your current age Your taxable income today

$

Age you'll start withdrawing

Age 65 · withdrawals begin in 10 yrs

Monthly income you want (after-tax, fixed)

$

$5,500/mo · $66,000/yr

Account

Account type

Converts directly — the full converted amount is treated as ordinary income in the conversion year.

Spread conversion over (laddered line)

5 years · one slice per year

Only affects the “spread over time” line. Smaller yearly slices stay in lower brackets, so the blended tax is lower than one lump. The slices stack on the income above — the biggest savings come from converting in low-income years (e.g., early retirement), which you can model by lowering “taxable income today.”

Taxes & surcharges

Filing status

State tax rate (%)

Future tax-rate risk (added to withdrawal-era ordinary rate)

+3 points assumed on future ordinary rates

OBBBA made today's brackets permanent — there's no scheduled hike — but many planners still assume rates could rise. Roth withdrawals stay tax-free regardless, so this only affects the IRA/401(k) path. Set to 0 to assume no change.

Other retirement income (Social Security, pension)

40% of today's income ≈ $100,000/yr

In retirement your IRA/401(k) withdrawals stack on top of this income, so they're taxed at higher brackets and push more toward IRMAA — Roth withdrawals don't. Defaults to ~40% of today's income (Social Security plus a pension or working spouse). Social Security alone replaces closer to 27–34% for higher earners, so lower this if these accounts will be your main source of income.

Apply Medicare IRMAA surcharge to IRA/401(k) withdrawals (65+)

Estimate NIIT 3.8% exposure on large withdrawals

IRMAA: traditional withdrawals raise MAGI and can lift Medicare Part B/D premiums (2026 starts at $109K single / $218K joint); Roth withdrawals don't count. NIIT isn't charged on the withdrawal itself, but a higher MAGI can expose your other investment income to the 3.8% tax — off by default.

Growth

Annual return (%) Plan through age

Starting balance$500,000

Roth Conv. + Offset
Roth Conv. — spread over time
Roth Conv. (pay the tax)
IRA / 401(k) — taxed on withdrawal

Converting and offsetting the tax leaves you with$0more in total value by your plan-end age than leaving it in a traditional IRA / 401(k).

Your results

Four paths, side by side

The same converted dollars by age 90 — after the IRS takes its cut on every path.

1 · Income analysis

How much you could live on each month

Level after-tax income from age 65 to 90, spending the account down to zero.

IRA / 401(k)$0

Every figure above traces back to these tables. Pick a path to see its annual calculation — all amounts are per year, with withdrawals starting at the age you set.

Select a path above to see its year-by-year calculation.

Total value = end-of-year balance + cumulative after-tax income withdrawn. Growth is applied to the balance remaining after each year's withdrawal.

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Calculator FAQ

"Account balance" shows what's left invested in each account (the traditional balance is pre-tax). The offset and IRA overlap until withdrawals start, then the IRA falls behind because it must withdraw more to net the same after-tax income. "Total value" adds the after-tax income you've already drawn to that balance, so the IRA tracks the offset during your working years and only diverges once withdrawals begin and each one is taxed. The traditional balance is shown before the income tax still owed on it, so the IRA's true after-tax worth is a bit lower than the line — which is exactly why converting has value.

A conversion adds the converted amount to your ordinary income for the year. This tool stacks the conversion on top of your current taxable income and applies the 2026 federal brackets for your filing status, then adds state tax.

Yes. Traditional withdrawals raise your Modified Adjusted Gross Income, which can push you into higher Medicare IRMAA tiers (2026 starts at $109K single / $218K joint) and raise your Part B and Part D premiums. Qualified Roth withdrawals aren't counted in MAGI, so they don't trigger IRMAA — one of the quieter advantages of converting.

The 2017 rates were made permanent by the 2025 OBBBA, so there's no scheduled increase. But future Congresses could still raise rates given federal deficits, and Roth withdrawals stay tax-free regardless — so a conversion is partly insurance against higher future rates. The Taxes tab lets you assume a rate increase (default +3 points) applied only to the IRA/401(k) path.

No. This is an educational estimate using 2026 federal brackets, a flat state rate, and simplifying assumptions. It doesn't model the pro-rata rule on after-tax basis, RMDs, Social Security taxation, AMT, inflation-adjusted withdrawals, or the two-year IRMAA lookback. Confirm with a qualified CPA or tax advisor before converting.