Roth conversion planning
Roth conversion IRMAA calculator
Roth conversions can be useful, but the taxable conversion amount may raise MAGI and trigger IRMAA. Use this what-if calculator before you convert.
Open main calculatorBefore you decide
- Confirm which tax year will be used for your Medicare premium notice.
- Estimate the taxable amount of the conversion, not the account balance.
- Compare a one-year conversion with splitting income across tax years.
Test a Roth conversion against 2026 IRMAA
Lump-sum projected MAGI
$125,000
Lump-sum annual IRMAA increase
$1,148.40
Split-per-year amount
$20,000
Annual IRMAA increase per split year
$1,148.40
Room before next IRMAA threshold
$4,000
Even split across years, each year still crosses an IRMAA threshold. Consider a smaller conversion or timing it around the two-year lookback.
What to watch
Taxable conversion amount
A Roth conversion generally adds taxable income in the year converted. That income can flow into MAGI.
Two-year lookback
Medicare IRMAA usually uses income from two years earlier, so a conversion can affect a later premium year.
Cliff thresholds
IRMAA thresholds are cliffs. A small extra conversion can move the full monthly surcharge into a higher tier.
Official sources
- CMS 2026 Medicare Parts A & B premiums and deductibles for Medicare Part B premium and IRMAA amounts.
- SSA Form SSA-44 for IRMAA life-changing event reconsideration.
- IRS Social Security income guidance for taxable Social Security benefit rules.