The Reason Everyone Gave for Converting to a Roth Just Disappeared. The Real Reason Did Not.

Joan retired last year at 64. She has a large traditional IRA, no paycheck anymore, and has not yet started Social Security. For a few years, her taxable income is going to be unusually low, and then it is going to climb, hard, when Social Security and required minimum distributions both switch on. Her advisor used to frame her Roth question around a deadline: convert before tax rates rise at the end of 2025. That deadline is gone. As of 2026, the better reason to convert is sitting right in front of her, and it has nothing to do with the calendar everyone was watching.

(Joan is a composite. The story is illustrative. The math is real and typical.)

The deadline that evaporated

For most of the last several years, the loudest argument for Roth conversions was a countdown. The 2017 tax cuts were set to expire at the end of 2025, rates were scheduled to jump, and the pitch was to convert while rates were still low. Then, in July 2025, the One Big Beautiful Bill Act made those lower rates permanent. The seven brackets, 10, 12, 22, 24, 32, 35, and 37 percent, are now the law going forward, not a temporary arrangement about to lapse.

So the urgency vanished. If you were going to convert only because rates were about to rise by statute, that reason is gone, and there is no penalty for having waited. But here is the part that got lost in the relief: the deadline was never the strongest argument. It was just the loudest. The real case for converting does not depend on the law changing at all. It depends on you.

The detonating number

Here is the whole article in one line. The tax on a Roth conversion is set by the bracket you fill when you convert. Joan can convert $50,000 in a low-income year and pay the 12% rate, or wait and convert the same $50,000 later when her income has climbed into the 22% bracket. The difference is 10 percentage points on $50,000, which is about $5,000 in tax, decided entirely by which year she chooses.

Why low-income years are the whole opportunity

The mechanism is bracket arbitrage. A conversion is taxed as ordinary income, so it stacks on top of whatever else you earn that year. In a low-income year, the early dollars of a conversion fill up the cheap brackets. In a high-income year, those same dollars pile on at the top of a more expensive one.

Joan's gap years, after the paycheck stops but before Social Security and required distributions start, are the cheapest brackets she will ever see again. Her standard deduction of $32,200 for a couple shields the first slice, and a wide 12% band sits above it. Every dollar she converts now at 12% is a dollar she does not have to distribute later at 22% or more, once her required minimum distributions begin and stack on top of Social Security. She is not avoiding tax. She is choosing to pay it in her cheapest years instead of her most expensive ones, and moving the money into an account that then grows and comes out tax-free, with no required distributions of its own.

The second-order benefit is the one heirs and surviving spouses feel. A traditional IRA passed to a surviving spouse often pushes that spouse into the higher single-filer brackets at the worst possible time. Money converted to a Roth in Joan's low years sidesteps that trap entirely.

Why the math is easy to get backward

The trap is treating a conversion as a cost to avoid rather than a bill to time. Paying tax voluntarily, in a year you did not have to, feels wrong, so people defer it. But deferring is not avoiding. The tax on a traditional IRA is owed eventually, and deferral simply hands the choice of bracket to your future self, who will likely be in a higher one once distributions and Social Security arrive together. The instinct to delay the tax is the instinct that converts at 22% instead of 12%, which on $50,000 is the difference of about $5,000.

One real caution sits next to the opportunity. A conversion raises your income for the year, which can ripple into Medicare's IRMAA surcharge two years later and into the taxation of Social Security. The move is to size each year's conversion to fill the cheap bracket and stop just short of those cliffs, not to convert everything at once.

How to use a window the law no longer forces

• Convert for your trajectory, not for a deadline, because the rates are permanent now and the only clock that matters is your own income, which is lowest in the gap years.
• Fill the cheap bracket and stop, since the value is in paying 12% on dollars that would otherwise come out at 22% or more, not in converting as much as possible.
• Watch the cliffs above the bracket, because a conversion that saves income tax can cost you in Medicare surcharges or Social Security taxation if you push too far in one year.
• Think in surviving-spouse terms, since money moved to a Roth in a low year spares a survivor the higher single-filer brackets later.

The deadline that drove Joan's old conversation is gone, and that is fine, because it was never the real reason. The real reason is that she is standing in the lowest-tax years of her retirement right now. Converting at 12% what would later come out at 22% is worth about $5,000 on every $50,000, and the only thing that window is waiting on is her.

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Joan is a composite character used to illustrate typical math. Her age and accounts are hypothetical; the 2026 tax brackets, the permanence of the rates under the 2025 law, and the conversion mechanics are real as of June 2026. Roth conversions affect Medicare premiums, Social Security taxation, and your full tax picture. This article is educational and is not financial or tax advice.

Related reading: how a Roth conversion interacts with IRMAA and the retirement tools we track.