Roth Conversions Before Age 63 Beat IRMAA
Roth conversions add to MAGI in the conversion year. Doing them before the IRMAA lookback window starts is the cleanest way to get the long-term Roth benefit without paying a Medicare surcharge.
Converting traditional retirement money to Roth is one of the highest-leverage moves in retirement planning. It locks in tomorrow's tax-free growth at today's tax rate. The IRMAA two-year lookback turns it into a timing problem.
The conversion math
A Roth conversion adds the converted amount to your AGI in the conversion year. Convert $80,000 and your AGI rises by $80,000. You owe income tax on the converted amount at your marginal rate. The converted dollars then grow tax-free in the Roth and avoid required minimum distributions later.
Why the year matters
Medicare uses the tax return from two years ago. Your 2026 premium reflects 2024 income. So a Roth conversion done at age 63 hits your Medicare premiums at age 65 and 66. A conversion at age 64 hits ages 66 and 67. A conversion at 65 hits 67 and 68. The window where conversions land in IRMAA is age 63 onward.
The pre-63 sweet spot
Conversions done at age 62 or earlier never touch Medicare. You still owe the income tax, but you skip the IRMAA surcharge entirely. For someone planning to retire in their early 60s, this is often a 2-3 year window of aggressive conversions before Medicare enrollment kicks in.
Bracket-stacking inside IRMAA
If you must convert after 63, fill exactly to the top of an IRMAA bracket. Crossing $216,000 of joint MAGI by $1 costs Tier 1 surcharge for both spouses, $1,776 of extra Medicare premiums per year (two beneficiaries x $74.10 Part B + $14.10 Part D x 12 months). Stop the conversion at $215,500 and you keep the IRMAA at zero.
The QCD alternative
Once you turn 70.5 you can use Qualified Charitable Distributions to send IRA money directly to charity, up to $108,000 in 2026. QCDs satisfy RMDs without adding to AGI, the cleanest IRMAA-friendly drawdown for charitably inclined retirees.
State income tax wrinkle
Some states tax retirement income, others do not. A retiree planning to move from California to Florida might delay conversions until after the move to avoid state tax. Combine that with the IRMAA timing and you can have a multi-year conversion plan that uses both federal and state-level rate arbitrage.
The widow penalty
When one spouse dies, the survivor files single the next year. The single brackets are roughly half the joint brackets, so a couple comfortably in joint Tier 0 can hit single Tier 2 the year after a death. Front-loading conversions while both spouses are alive can lock in the joint brackets.
Modeling tools
Run the calculator above with your projected MAGI for the conversion year. Then run it again at the next bracket up. The difference is your IRMAA cost of crossing the line. Compare that against the lifetime tax savings of the conversion to decide.