Roth Conversions in Your Sixties: The Window Most People Miss

A couple I'll call Linda and Dave came in last spring. Both 62, both just retired — Linda from healthcare administration, Dave from an engineering job. They had done well: $1.2 million between IRAs and 401(k)s, plus about $300,000 in non-IRA brokerage accounts, plus a paid-off house. They had pensions covering most of their basics and Social Security on the way at 67. Linda asked me a question that gets to the core of this article. She said, "Matt, we've been told to wait until 70 to take Social Security. We won't have RMDs until 73. So what do we do for income for the next eleven years — and is there any tax planning move we should be making in there?" Right? That's the right question. Most retirees never ask it. Linda did. Let me walk you through what we found.

The years between retirement and RMD age — required minimum distribution age, currently 73 under SECURE 2.0, going to 75 in 2033 — are what tax planners call the conversion window. They're the years when your taxable income is, on average, lower than it will be later in retirement. No more W-2 wages. RMDs haven't started. If you're delaying Social Security to 70, that income hasn't kicked in yet either. For most retirees, these are the lowest-tax years of the rest of their lives. And they only last until the RMDs hit.

Used well, the conversion window is when you systematically convert traditional IRA dollars to Roth IRA dollars at low tax brackets, before bigger income forces you into higher brackets later. Used poorly — or ignored — and you wake up at 73 watching RMDs push your income into the 22%, 24%, even 32% bracket and trigger IRMAA surcharges on top of the tax. The difference between using the window and not using it can run into six figures over a long retirement. Brutal if you miss it. Powerful if you don't.

What a Roth conversion actually is

A Roth conversion is moving money from a traditional IRA (or 401(k)) into a Roth IRA. Two important facts about it:

• The amount you convert is fully taxable in the year you convert. If you move $50,000 from your traditional IRA to your Roth IRA, $50,000 is added to your taxable income for that year. You owe ordinary income tax on it.
• Once the money is in the Roth IRA, future growth and withdrawals are tax-free — assuming you wait the required holding periods, which we'll cover below.

So the trade is: pay tax now at today's rate, get tax-free growth and tax-free withdrawals for the rest of your life. The math depends on whether your future tax rate (or the tax rate of your heirs) is higher than today's rate. If you'll be in a higher bracket later, conversion saves money. If you'll be in a lower bracket later, conversion may not pay off. The art is figuring out which one you are.

Why "your sixties" specifically

Most pre-retirees have their highest taxable income in their forties and fifties — peak earning years. Then they retire. W-2 income drops to zero. Pension and rental income may continue, but for most households, the ten years between retirement and RMD age are the lowest-tax years they will ever experience. After RMD age, traditional IRA distributions are forced — by law — and they push income up.

So the strategy is: in the conversion window, convert traditional IRA dollars at today's lower brackets. By the time RMDs start, the converted dollars are in the Roth, where RMDs don't apply (Roth IRAs have no required distributions during the original owner's lifetime). The forced withdrawals in your seventies and eighties shrink, your taxable income shrinks, your IRMAA surcharges shrink, and your overall lifetime tax bill shrinks. Sometimes by a lot.

The "bracket fill-up" strategy

The most common conversion approach is to convert each year up to the top of a target tax bracket — and stop. The thinking: pay tax at the 12% rate this year on conversion dollars rather than pay tax at the 22% rate on those same dollars in your seventies when RMDs force them out. The 10-percentage-point spread, compounded across years and across multiple conversions, becomes meaningful money.

For Linda and Dave in 2026, here's what the math looked like:

The dollar difference over a long retirement, depending on assumptions, can easily be $80,000 to $150,000 in lifetime taxes saved. For Linda and Dave's situation, the conversion strategy was a clear win.

The IRMAA trap that ruins conversion plans

Here is the move that wrecks more conversion plans than any other: people start converting at 63 or 64 — before Medicare eligibility — and then keep converting at 65 and 66 without realizing that now their conversions are pushing their MAGI into IRMAA territory. The two-year look-back means that conversions at 63 and 64 hit Medicare premiums at 65 and 66.

If you read our earlier IRMAA article, you know the brackets in 2026 start at $218,000 of joint MAGI. So a couple converting $100,000 a year — without watching the bracket — can cross into IRMAA territory and trigger thousands in extra Medicare premiums two years later. Your conversion saved 10 percentage points on the income tax. The IRMAA surcharge gave back $4,000 of it. Net win is shrunk meaningfully.

The fix is to plan conversions to stop at the IRMAA bracket line, not just the income tax bracket line. For most retirees the IRMAA threshold sits between the 22% and 24% federal income tax brackets, so conversions filling the 12% and 22% brackets typically stay clear of IRMAA. But the planning has to look at both numbers, not just one.

The five-year rule (only matters under 59½)

One technical point worth knowing. Each Roth conversion has its own five-year clock. If you convert at 64 and try to withdraw the converted principal at 65, you owe no tax (since you already paid it on conversion) and no early-withdrawal penalty (since you're over 59½). But the earnings on those converted dollars don't qualify for fully tax-free treatment until your first Roth IRA's five-year clock has run.

For most retirees over 59½, this rarely matters in practice — the tax-free earnings rule almost always lines up with how they'd actually use the Roth in retirement (withdrawing earnings later, not immediately). For someone under 59½ doing conversions, the five-year rule is more critical. If you're in your sixties, just make sure you have some Roth IRA that's been open at least five years before you start drawing earnings tax-free.

When conversions DON'T make sense

Let me be balanced. There are situations where Roth conversions are the wrong move:

• You're in a high bracket today and you'll be in a low bracket forever in retirement. If your only retirement income will be a small Social Security check and a small IRA, you may always stay in the 12% bracket — no benefit to converting.
• You can't afford the tax with non-IRA cash. If you have to use IRA dollars to pay the tax on the conversion, the math gets significantly worse — you're effectively selling off some of the money you're trying to grow tax-free.
• You're charitably inclined and plan to use QCDs aggressively. Qualified Charitable Distributions from a traditional IRA after age 70½ are excluded from income — so traditional IRA dollars going to charity are more tax-efficient than Roth dollars in that specific case.
• You expect tax rates to be lower in the future — a contrarian view, but legitimate. If you genuinely believe tax rates will fall and yours specifically will fall, deferring is the right call.

The OBBBA-extended tax brackets — which made the TCJA rate structure permanent in 2025 — locked in the current bracket structure for the foreseeable future. So the "rates will spike when TCJA expires" argument that drove a lot of 2024 conversion planning has cooled off. But the basic logic of converting in your low-income sixties versus paying RMDs in your higher-income seventies still holds, regardless of legislation.

The annual conversion checklist

• Estimate this year's taxable income before any conversion. Pension, interest, dividends, Social Security if applicable, capital gains.
• Calculate the room to the top of your target bracket. 12%, 22%, or sometimes 24% are the most common targets.
• Subtract the IRMAA bracket buffer. Keep MAGI under the IRMAA threshold unless the math at higher brackets justifies it.
• Convert by December 31 of the target year. Conversions must be completed in the calendar year — they cannot be backdated.
• Pay the conversion tax with non-IRA money if possible. Using IRA dollars to pay the tax shrinks the converted amount.
• Re-run the projection every year. Income changes, rates change, brackets change — annual re-evaluation matters.

What this looks like in practice

Linda and Dave settled on a conversion plan: $50,000 per year, every year, from age 62 through age 70 — when Social Security starts. That kept them in the 12% bracket throughout, well under the IRMAA threshold, and converted roughly $400,000 over the eight-year window. The taxes paid on those conversions averaged about $5,500 a year. The lifetime tax savings, projected over their joint life expectancy plus the next-generation impact for their kids who would inherit Roths instead of traditional IRAs, came out to roughly $130,000 in present value. Eight years of paperwork. One six-figure shift in family wealth. Sleep at night.

This is the kind of planning that produces meaningful dollar savings and does not show up in any conversation between you and a 401(k) provider. It requires a written plan, a tax projection, and someone who understands the interaction between federal brackets, IRMAA, and Social Security. We do this analysis as part of a written-plan consultation, in coordination with your CPA where helpful.

The bottom line

The years between retirement and RMD age are typically the lowest-tax years of the rest of your life. Used well, they're a powerful conversion window — moving traditional IRA dollars into Roth at low brackets before bigger income forces higher brackets later. Used poorly or ignored, the same dollars come out in your seventies at higher brackets, with IRMAA surcharges on top. The difference can be six figures in lifetime taxes for a typical $1M+ retiree. The window is open. The window closes when RMDs start. Don't sleep through it.