A Roth conversion moves dollars from tax-deferred to Roth, paying ordinary tax now to shrink RMDs and future tax later. The projection models them year by year, inside the full tax picture.
Two strategies
- Fill to a ceiling. Each year, convert just enough to bring ordinary income up to a chosen ceiling, such as a tax-bracket top or a Medicare IRMAA MAGI cliff. Automatically heavy in low-income years and light (or skipped) when RMDs and other income already fill the bracket. Ceilings are phased: target a low bracket early, a higher one later, stop at a chosen age.
- Custom amounts. Explicit dollar phases you set per age range.
Details that change the answer
- Conversions are taxed as ordinary income and funded per your draw order. To keep living expenses from eating the bracket headroom, put Roth ahead of tax-deferred in the draw order for the phase covering your conversion years. The plan never switches the order for you.
- If you're on a marketplace health plan, the ACA cliff is usually the binding ceiling before 65. One converted dollar too many can cost a whole year's subsidy.
- The with-vs-without comparison shows exactly the RMD and tax stream a conversion plan erases, alongside lifetime tax and ending value.
The optimizer's frontier re-runs the same engine over a grid of ceilings on identical seeded paths, so differences between candidates are real, not luck.