The untouched IRA
The "do nothing" scenario: no withdrawals, no conversions, until the IRS insists.
The RMD wave
Each bar is a forced distribution — ordinary income whether you need it or not. Bar color shows the Medicare IRMAA tier the year's income lands in (thresholds compared in today's dollars; premiums bite two years after the income).
The conversion window
Every year before RMDs is bracket space that expires unused. This is how much could move from traditional to Roth each year without crossing each line — the torpedo already accounted for.
"To first IRMAA cliff" is the conversion that lands MAGI exactly at the first Medicare threshold — relevant from age 63 on, since premiums look back two years. The Marginal Rate Explorer prices any amount in between; the Roth conversion tool models whether the move pays.
Year-by-year table — show your work
How the math works
The wave
The balance compounds at your blended rate until RMD age — 73 if you were born in the 1950s, 75 if 1960 or later — then each year the IRS forces out last year's balance divided by the Uniform Lifetime Table factor (26.5 at 73, 24.6 at 75, falling every year). Early on, growth usually outruns the divisor, so the forced distributions rise for years — the wave builds before it breaks. Every dollar is ordinary income stacked on your Social Security (through the provisional-income formula) and pension.
The window
Before the wave, your brackets sit mostly empty — and empty bracket space doesn't roll over. The table solves, for each year, the gross conversion that would land taxable income exactly at the top of the 12%, 22%, and 24% brackets, and the amount that would land MAGI exactly at the first IRMAA threshold. The Social Security interaction is solved, not ignored: conversions raise provisional income, which makes more of the benefit taxable, which shrinks the room. Once RMDs start, the forced distribution eats the room first — which is why the window rows stop at RMD age.
What this tool is not
A deliberately extreme baseline: nobody spends nothing from an IRA for decades, and RMD dollars here simply exit the projection rather than landing in the taxable account (in reality the after-tax remainder keeps compounding there — see the Withdrawal Order Sandbox for the full household picture). Brackets, deductions, and IRMAA thresholds are indexed forward at your inflation number; the §86 Social Security thresholds stay frozen, as in law. IRMAA is per person with a two-year lookback; surcharge dollars shown are today's amounts scaled by your inflation. Not modeled: state tax, NIIT, the 2025–2028 senior deduction, spouse age differences, QCDs (which can offset RMD income directly from age 70½ — a real lever this tool doesn't price).