Roth Conversion Windows by Age

When is the best time in your life to convert a traditional IRA to a Roth? The years after you stop working and before the forced income starts. A Roth conversion means moving money from a tax-deferred IRA into a Roth IRA, paying ordinary income tax on the amount now, in exchange for tax-free growth and withdrawals later, with no required minimum distributions ever. The whole game is doing it in the years your tax rate is lowest. For most affluent retirees that’s a specific, short window, and the calendar matters more than the dollar amount.

The conversion window by age

Think of your tax rate across retirement as a valley. While you work, income and rates are high. Once Social Security and RMDs switch on, they climb again. Between those two peaks sits the valley, the low-rate years, and that’s where conversions belong.

• Late 50s and early 60s, still working: Usually too expensive. Your income is near its peak, so converting stacks on top at a high rate. Exceptions are a gap year, a sabbatical, or a layoff.
• Early 60s after retiring, before Social Security: The prime window. Wages have stopped, Social Security hasn’t started, RMDs are years off. Taxable income can drop to its lowest point in decades, leaving room to convert and fill up the low brackets cheaply.
• Mid-to-late 60s, before claiming Social Security and before Medicare’s income lookback bites: Still strong, but watch the edges. Once you’re near 63, conversions start affecting Medicare premiums two years out.
• 70 to your RMD start age (73 or 75): The closing window. RMDs haven’t begun yet, so there’s still room, but it’s shrinking fast. Convert aggressively here if you haven’t already, because once RMDs start the forced income fills the brackets first.

There’s no income limit on a conversion, by the way. The Roth contribution phase-outs don’t apply. Anyone can convert any amount at any income, which is exactly why the timing, not eligibility, is the whole decision.

Fill the bracket, don’t blow past it

The core technique is bracket-filling. Look at the 2026 brackets and convert just enough to reach the top of a target bracket, then stop. For a married couple filing jointly, the 22% bracket runs up to $211,400 of taxable income and the 24% bracket up to $403,550. A common plan converts up to the top of the 24% bracket in the valley years, on the bet that future RMDs would otherwise push that same money out at a higher rate.

A worked example. A 64-year-old couple retired, not yet on Social Security, has $90,000 of taxable income before converting. The top of their 24% bracket is $403,550. That leaves roughly $313,000 of room to convert at 24% or less. Fill a chunk of it each year through their late 60s, and they move hundreds of thousands into the Roth before RMDs ever begin, money that then grows tax-free and never gets divided by an RMD factor.

The hidden price most people miss

Here’s the second-order effect that traps the impatient. A conversion is ordinary income, so it can raise the tax on your Social Security, and it sets your Medicare premiums two years later through IRMAA, the income-based surcharge. Because of that two-year lookback, a conversion at 63 shows up in your Medicare bill at 65. Convert too hard and you save on future RMDs but overpay on premiums and Social Security taxation right now. The art is filling the bracket without spilling into the next IRMAA tier.

If your accounts are large

The bigger your tax-deferred balance, the more the window is worth, and the more it pays to start early, because you can only convert so much per year before the rate gets ugly. Spread conversions across every valley year you have rather than cramming them into one. Coordinate with capital gains harvesting so the two strategies share the room instead of fighting for it. And remember the legacy angle: a Roth your heirs inherit comes out tax-free over their ten-year payout window, while a traditional IRA lands on top of their peak-earning incomes. For a family planning to leave money behind, converting in your valley can move the tax off your heirs’ highest-rate years entirely.

The conversion window opens the day your paycheck stops and starts closing the day RMDs begin. It’s a handful of years, and it’s the cheapest your tax rate will ever be again. Find your valley, fill the bracket, and get the money moved before the window shuts.