Roth conversions in retirement: is it worth it?

A Roth conversion means moving money from a traditional, tax-deferred account into a Roth account, paying ordinary income tax on the converted amount now in exchange for tax-free growth and withdrawals later. It’s a genuinely useful tool in some situations and a costly mistake in others — the difference comes down to a few specific conditions.

The basic trade-off

Converting triggers an immediate tax bill on the amount converted, at ordinary income rates, in the year of the conversion. In exchange, that money — and all future growth on it — becomes tax-free when eventually withdrawn, and Roth IRAs carry no required minimum distributions during the original owner’s lifetime. The IRS’s overview of traditional and Roth IRAs covers the mechanics of how a conversion is processed and reported.

When it tends to make sense

Lower-income years. The years between retiring and claiming Social Security (or before RMDs begin at 73) are often a window of unusually low taxable income — converting in those years means paying tax at a lower rate than would otherwise apply later. This is the scenario most often cited as the strongest case for conversion.

Reducing future RMDs. A large traditional account balance generates large mandatory distributions starting at 73, which can push income into higher brackets later in life. Converting some of that balance earlier, in lower-income years, can reduce the eventual RMD burden.

Estate planning. Roth accounts pass to heirs without the income tax liability that traditional accounts carry, which can make conversion attractive for someone primarily focused on what’s left to heirs rather than their own spending needs.

When it tends not to make sense

If it pushes you into a meaningfully higher bracket or triggers IRMAA. Converting a large amount in one year can spike income enough to cross a tax bracket threshold or an IRMAA threshold (see IRMAA: when Medicare costs more because of your income) — sometimes making the immediate cost of converting larger than the long-term benefit.

If you expect to be in a lower tax bracket later anyway. If future income (and the resulting tax rate on eventual withdrawals) is expected to be lower than your current rate, paying tax now at a higher rate works against you.

If you’ll need the converted funds soon. Converted amounts generally need to remain in the Roth for five years before being withdrawn penalty-free if you’re under 59½, even though the original contribution basis isn’t taxed again — a detail worth checking before converting funds you might need access to soon.

How to think about sizing a conversion

Rather than converting an entire balance at once, many people convert smaller amounts over several years, intentionally filling up a specific tax bracket each year without spilling into the next one — sometimes called bracket-filling. Withdrawal strategy basics covers how this kind of year-by-year income planning fits alongside other retirement income decisions.

Where to get personalized guidance

Conversion decisions interact with tax brackets, IRMAA, RMDs, and estate goals in ways that are genuinely hard to model without running actual numbers. A tax professional or fee-only financial planner can project the specific tax cost and long-term benefit for your situation before converting anything.

Related reading: IRMAA: when Medicare costs more because of your income and Required minimum distributions, explained.