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Roth Conversion Cost Checker

Before 65, the tax bill is often the smaller cost. See whether a conversion pushes you over the ACA subsidy cliff or into a Medicare surcharge. Educational only.

Roth conversion inputs

Converting $15,000 at an effective rate of 14.3%

The tax bill is the smaller half of this.

Federal income tax now

$2,150

Income after converting

$70,000
This conversion pushes you over the ACA subsidy cliff. You had $7,600 of income room before the cliff at $62,600. Converting $15,000 takes you past it — and one dollar over means you lose your entire premium tax credit for the year, not a slice of it. For a 60-year-old that is frequently worth more than five figures. See what it costs. Converting $7,600 or less would stay under it.

Roth conversion calendar: what each year touches

This is a coordination map, not a schedule telling you to convert. It uses age 61 in 2026 to estimate birth year 1965; confirm exact birthday-based rules before acting.

Annual Roth conversion considerations for ACA coverage, Medicare, Social Security, and required minimum distributions
Year / ageCoverageIncome interactionSocial SecurityRMD context
2026Age 61Marketplace / employer / other pre-Medicare coverageConversion counts in ACA MAGI if using Marketplace coverageBefore earliest retirement-benefit claim ageBefore RMD age 75
2027Age 62Marketplace / employer / other pre-Medicare coverageConversion counts in ACA MAGI if using Marketplace coverageSocial Security claiming windowBefore RMD age 75
2028Age 63Marketplace / employer / other pre-Medicare coverageConversion counts in ACA MAGI if using Marketplace coverageSocial Security claiming windowBefore RMD age 75
2029Age 64Marketplace / employer / other pre-Medicare coverageConversion counts in ACA MAGI if using Marketplace coverageSocial Security claiming windowBefore RMD age 75
2030Age 65MedicareIncome can affect Medicare premiums at 67Social Security claiming windowBefore RMD age 75
2031Age 66MedicareIncome can affect Medicare premiums at 68Social Security claiming windowBefore RMD age 75
2032Age 67MedicareIncome can affect Medicare premiums at 69Social Security claiming windowBefore RMD age 75
2033Age 68MedicareIncome can affect Medicare premiums at 70Social Security claiming windowBefore RMD age 75
2034Age 69MedicareIncome can affect Medicare premiums at 71Social Security claiming windowBefore RMD age 75
2035Age 70MedicareIncome can affect Medicare premiums at 72Delayed retirement credits no longer increase after 70Before RMD age 75
2036Age 71MedicareIncome can affect Medicare premiums at 73Delayed retirement credits no longer increase after 70Before RMD age 75
2037Age 72MedicareIncome can affect Medicare premiums at 74Delayed retirement credits no longer increase after 70Before RMD age 75
2038Age 73MedicareIncome can affect Medicare premiums at 75Delayed retirement credits no longer increase after 70Before RMD age 75
2039Age 74MedicareIncome can affect Medicare premiums at 76Delayed retirement credits no longer increase after 70Before RMD age 75
2040Age 75MedicareIncome can affect Medicare premiums at 77Delayed retirement credits no longer increase after 70First RMD year under current law

Highlighted transition rows include age 63 (the tax year generally used for age-65 IRMAA), age 65 (Medicare eligibility), and the estimated RMD start age. Actual Marketplace enrollment, employer coverage, filing status, Social Security timing, and workplace-plan exceptions can change the relevance of a row.

The decision in one line. Convert to Roth if your tax rate is lower today than it will be in retirement; stay traditional if it is higher. Nobody knows their future rate for certain, which is why splitting between the two is a reasonable hedge — and why capturing the full employer match beats this question entirely.

What most calculators miss. Between 60 and 65 the income tax is often the smaller cost. A conversion raises the income figure used for ACA subsidies, and since the enhanced credits expired at the end of 2025, one dollar over 400% of the poverty line forfeits the whole credit. From 63, it separately raises your Medicare premium two years later. These are the years to convert deliberately, not casually.

Federal tax only — it ignores state tax, capital gains stacking, and the taxation of Social Security benefits, and it models the first IRMAA tier only (higher tiers cost more). ACA MAGI counts traditional withdrawals, conversions, capital gains, pensions and all Social Security benefits; Roth withdrawals do not count. An educational estimate, not tax advice — a conversion is exactly the decision worth checking with a qualified professional.

Numbers behind this result

Open the exact public record for the legal figure or modeling convention used above.

Sources and notes

  1. Roth Comparison ChartInternal Revenue Service
  2. Rev. Proc. 2025-32 (2026 brackets and standard deduction)Internal Revenue Service
  3. 2026 Medicare Parts A & B Premiums and Deductibles (IRMAA)Centers for Medicare & Medicaid Services
  4. How will the loss of enhanced premium tax credits affect older adults?KFF

These tools use simplified assumptions. Use them to frame better questions, then verify details against primary sources or a qualified professional.