The Roth conversion window most retirees miss

After you stop working but before required minimum distributions begin, your taxable income is often the lowest it will ever be. That window lets you convert money from a pre-tax IRA to a Roth at lower tax rates. The goal isn't to convert everything at once. It's to fill up your lower tax brackets gradually, year by year, so taxes don't spike later.

Why this window exists

Required minimum distributions, the amounts the IRS makes you withdraw from pre-tax retirement accounts, now begin at age 73. For many people, the years between retiring and that first required withdrawal are a quiet low point in taxable income. Paychecks have stopped, and the forced withdrawals have not started. Sometimes full Social Security hasn't started either.

That dip is easy to overlook, because nothing forces you to act. But it is one of the few times in life you get to choose how much income to recognize, and at what rate.

What a Roth conversion does in these years

• Moves money from a pre-tax IRA into a Roth, where it grows and is later withdrawn tax-free
• Lets you pay tax now, at a rate you can see, instead of an unknown future rate
• Shrinks the pre-tax balance that will drive your future required withdrawals
• Can reduce how much of your Social Security becomes taxable down the road

The goal is to fill brackets, not empty the account

The mistake is treating a conversion as all-or-nothing. Convert too much in one year and you can push yourself into a higher bracket, raise your Medicare premiums two years later, and trigger more tax on your Social Security. The better approach is to convert just enough each year to fill up a lower bracket, then stop. Done patiently over several years, this smooths your lifetime tax bill instead of letting it spike when required withdrawals and a surviving spouse's single tax brackets arrive.

Frequently asked questions

When is the best time to do a Roth conversion?

Often in the lower-income years after you retire but before required minimum distributions begin at 73. The exact timing and amount depend on your tax brackets, other income, and Medicare premium thresholds, so it is worth modeling year by year.

Will a Roth conversion affect my Medicare premiums?

It can. A large conversion raises your income, and Medicare looks back two years to set Part B and Part D premiums. Sizing conversions to stay under the relevant thresholds is part of doing them well.