The Roth Conversion Window

A Roth conversion moves money from a pre-tax retirement account into a Roth IRA. You pay income tax on the amount converted now; in exchange, that money — and everything it earns — comes out tax-free later, with no required minimum distributions during your lifetime. The entire question is whether your tax rate today is lower than your rate will be later. For many people, there's a stretch of life where the answer is clearly yes.

The window

Between your last paycheck and your first Social Security check, income often drops to the lowest level of your adult life — while your future RMDs keep quietly growing. Those years can allow you to convert meaningful amounts while 'filling up' low tax brackets, shrinking the pre-tax balance that would otherwise produce large taxable RMDs (and potentially higher taxes on your Social Security) for decades.

What careful conversion planning watches

• Bracket management. Convert enough to use a low bracket, not so much that you spill into a high one — this is a dial, not a switch.
• Medicare IRMAA. Conversion income two years before and during Medicare can trigger premium surcharges; the cliff is exact, not gradual.
• The five-year rules and timing. Converted amounts have their own clocks; conversions late in life still work but the math changes.
• The pro-rata rule. If you hold pre-tax and after-tax IRA money, conversions are taxed proportionally — you can't cherry-pick the after-tax dollars.
• Paying the tax from outside the IRA. Conversions work best when the tax bill is paid from taxable savings, letting the full converted amount keep compounding.
• Heirs. Under current law most non-spouse heirs must empty inherited retirement accounts within 10 years — Roth dollars make that a tax-free event instead of a taxable one.