Roth Conversions in the 62–70 Window: A Complete Strategy Guide

A Roth conversion is one of the few moves in retirement where the timing matters more than the amount. The years between your last paycheck and your first required distribution — usually somewhere in the 62-to-70 range — are the cheapest tax bracket most people will ever live in. The big salary has stopped, required minimum distributions at 73 have not started, and in many households Social Security has not started either. For a few years, taxable income falls into a valley, and that valley is the single best window to move money out of a traditional IRA and into a Roth at a known, low rate.

I walk households through this decision constantly, and the conversation always covers the same ground. What a conversion actually is and how it differs from a contribution. Why the 62-to-70 window is the sweet spot. How much to convert in a given year. The traps that quietly cost people thousands. And — just as important — who should not do this at all. This piece is that walkthrough, in order.

What a Roth conversion actually is

A Roth conversion is the act of moving money out of a traditional IRA or 401(k) and into a Roth account, and paying the ordinary income tax on it in the year you move it. That is the whole transaction. Every dollar you convert is added to your taxable income for that year, you pay tax on it at your marginal rate, and from then on the money lives in the Roth — where it grows tax-free, comes out tax-free in retirement, and carries no required minimum distributions during your lifetime.

The thing people mix up is the difference between a conversion and a contribution. A contribution is new money you add to a Roth from earnings, and it is capped each year by IRS limits and income phase-outs. A conversion is not new money and is not capped — it is money you already have inside a traditional account, repositioned into the Roth bucket. There is no income limit on who can convert and no dollar ceiling on how much you can convert. You can convert $10,000 or $300,000 in a single year. The only real constraint is the tax bill, and that constraint is exactly what makes the timing decision matter so much. You are choosing, deliberately, to pay tax now instead of letting the IRS collect it later on a balance that may be much larger.

Why the 62–70 window is the sweet spot

Picture a typical income timeline. While you are working, your salary fills up the tax brackets and a conversion would stack on top at your highest rate — expensive. At 73, required minimum distributions begin, the IRS forces taxable money out of your traditional accounts whether you need it or not, and that forced income often arrives right alongside Social Security. Between those two phases sits the gap: you have retired, the paycheck is gone, and the forced withdrawals have not started. Income drops to a lifetime low.

That gap is the opportunity. In those years you may be sitting in the 12% or 22% bracket when the rest of your retired life will be spent higher, because a traditional IRA that keeps compounding produces larger and larger required distributions the longer you wait. Convert during the valley and you pay tax at a rate you can see today. Skip the valley and you do not avoid the tax — you defer it onto a bigger balance, taken at a time when you no longer control the timing.

The problem a conversion defuses is the stacking problem. Once RMDs land on top of Social Security, two streams of forced income pile up in the same brackets, and the combination can push a household into a higher rate than they ever paid while working. Moving money out of the traditional account ahead of time shrinks the balance that drives those future RMDs. You are not eliminating tax; you are choosing to pay it in the cheapest year available rather than the most expensive one.

How much should you convert?

The honest answer is "enough to fill the cheap brackets, and not a dollar more." The technique most planners use is bracket topping. You start with your projected taxable income for the year, look at how much room is left before the top of your current bracket, and convert just enough to fill that room without spilling into the next one. If you are a married couple sitting near the top of the 12% bracket, you might convert up to the 22% line and stop. The next year you do the math again.

This is where the difference between your marginal rate and your effective rate matters. Your marginal rate is what the next converted dollar costs; your effective rate is the blended average across everything you earn. A conversion is priced at the margin, so the question is never "what is my average tax rate" — it is "what does the next chunk cost me, and is that cheaper than what the same chunk will cost once RMDs and Social Security are running?" When the answer is yes, you convert up to the point where the marginal cost starts climbing.

Because a single year of bracket topping rarely clears a large traditional balance, most people convert across several years — a ladder. You spread the conversions over the whole 62-to-70 runway, taking a measured slice each year, so no single year gets pushed into a painful bracket. And there is a second ceiling to watch beyond the tax brackets: the IRMAA tiers that set Medicare premiums. A conversion can be perfectly fine on the income-tax side and still trip a Medicare surcharge, so the real target each year is the lower of the two ceilings — under the next tax bracket and under the next IRMAA tier. The IRS does not cap the conversion amount, but it does treat every converted dollar as ordinary income; for the mechanics, the IRS's Roth IRA guidance is the primary source. Run the numbers against both ceilings before you pull the trigger.

The traps that catch people

A conversion done without looking around the corner can cost more than it saves. These are the five that catch people most often:

• The IRMAA two-year lookback. Medicare sets your Part B and Part D premiums using your income from two years earlier, and IRMAA is a cliff — one dollar over a threshold bumps you into a full higher tier. A large conversion at 63 can raise your Medicare premiums at 65, so conversions are almost always sized to stay under the next tier.
• The Social Security tax torpedo. If you have already started collecting, a conversion adds income that can drag more of your Social Security benefit into the taxable column — up to 85% of it. That extra layer is a big reason people do their largest conversions before they file, while there is no benefit to torpedo yet.
• The two 5-year rules. One clock governs whether earnings come out tax-free — five years since your first Roth, and age 59½. A separate clock applies to each conversion before that principal can be withdrawn penalty-free if you are under 59½. Most people converting in their sixties are already past 59½, so the earnings clock is the one to mind.
• Paying the tax from the IRA itself. Withhold the tax out of the converted money and you shrink the amount that actually lands in the Roth — and if you are under 59½, that withheld piece can count as an early distribution with a penalty. Pay the tax from a taxable account instead, so the full converted amount makes it across and grows tax-free.
• State-tax timing. A conversion is taxed by the state you live in when you convert. If a move to a no-income-tax state is on the horizon, converting a year too early can hand your current state a tax bill you could have avoided by waiting until after you relocate.

Who should not convert

A conversion is a good tool, not a universal one, and part of doing this honestly is knowing when to leave it alone. There are several households where I usually advise against converting, or at least against converting much.

If you are already in the top bracket and expect to stay there, the core premise is gone — you would be paying tax at a high rate now to avoid a tax that is no higher later. If you do not have outside cash to cover the tax, a conversion forces you to fund the bill from the IRA itself, which gives back most of the benefit. If you plan to give heavily to charity, qualified charitable distributions let you move traditional-IRA money to charity tax-free after 70½, which is often a cleaner answer than converting and then donating.

Two more cases. If your heirs are in lower tax brackets than you, it can make more sense to let them inherit the traditional account and pay the tax at their lower rate than for you to prepay it at yours. And if you will need the money in the next few years, there is no time for tax-free growth to outrun the tax you just paid — the conversion has to have years to work. None of this means a conversion is wrong for you; it means the answer depends on your numbers, and sometimes the right move is to do nothing.

A multi-year conversion ladder in practice

Here is how the ladder looks for an illustrative household — a couple retiring at 63 with most of their savings inside a traditional 401(k) and a few years before either of them plans to claim Social Security. They have a taxable brokerage account to live on and to pay the conversion tax from, which is what makes the strategy work.

Year one, at 63, they project their income, find they are sitting low in the 12% bracket, and convert enough to fill the 12% bracket without crossing into 22%. They pay the tax from the brokerage account so the full amount lands in the Roth. The next year they do it again — but the numbers are not identical, because their balances have changed, the brackets have shifted with inflation, and they are now one year closer to Social Security and to Medicare. So they re-run it from scratch every year, checking both the bracket ceiling and the IRMAA tier before deciding the size.

They keep stepping up the ladder through the 62-to-72 runway, converting a measured slice each year, shrinking the traditional balance before RMDs at 73 force the issue. By the time required distributions begin, the traditional account is smaller, the forced income is lower, and a large pool of money sits in the Roth growing tax-free with no distributions required. The ladder is not a one-time calculation. It is the same decision, made fresh each year.

How conversions fit the bigger plan

A Roth conversion is one lever, not the whole machine. It only works well when it is coordinated with everything else happening in those years — which account you draw on for living expenses, when each spouse files for Social Security, how the brackets and IRMAA tiers line up, and what the withdrawal sequence looks like across the whole retirement. Pull the conversion lever in isolation and you can easily trip one of the traps above.

For the full tax-aware withdrawal sequence that ties conversions together with pension elections, RMDs, and asset location, see our complete guide to retirement income planning. And because the conversion window and the filing decision are so tightly linked, it is worth reading our Social Security claiming strategy alongside this one — the years you delay filing are often the same years you want to be converting.

The conversion window is narrow and it does not reopen. If you would like a second set of eyes on whether converting makes sense for your situation — and how much, in which years — our free Retirement Check-Up is a no-pressure conversation, zero cost and zero obligation. We do this work every day for households in Bloomfield Hills, Troy, Auburn Hills, and across Metro Detroit.