Taxpayers who experience a sharp drop in earnings this year face a time-sensitive decision: whether to move pretax retirement savings into a Roth IRA while their income, and therefore their federal tax bracket, sits well below normal. Because the converted amount is taxed as ordinary income in the year it moves, a low-income year can cut the upfront bill by thousands of dollars and shield every future qualified withdrawal from higher rates. The IRS has already published the 2026 rate schedules and bracket thresholds, giving filers a clear picture of what they will owe if they act before December 31.
Why a low-income year changes the Roth conversion math
A Roth conversion works by transferring money from a traditional IRA, where contributions were tax-deferred, into a Roth IRA, where qualified withdrawals come out tax-free. The catch is that the transferred amount counts as taxable income in the year of the switch. Under Section 408A of the Internal Revenue Code, the taxable portion of a conversion is the amount that would have been includible in gross income had it simply been distributed. That means the cost of converting is driven entirely by where the additional income lands on the rate schedule for that particular tax year.
When someone’s wages, business income, or capital gains fall well below their historical average, the gap between their actual taxable income and the top of their current bracket can absorb a sizable conversion at a lower marginal rate. A person who normally earns enough to sit in the 24 percent bracket but whose income drops into the 12 percent bracket for one year can convert traditional IRA dollars at roughly half the usual federal rate. The savings compound over decades because every dollar inside the Roth grows and is eventually withdrawn free of federal income tax.
Treasury regulations reinforce this treatment. According to 26 CFR Section 1.408A-4, taxable conversion amounts are included in gross income for the year of conversion “for all purposes,” with only limited exceptions. There is no mechanism to spread the tax hit across multiple years or defer it. The rate that applies is locked the moment the calendar year closes.
2026 bracket thresholds and the One, Big, Beautiful Bill adjustments
Knowing the exact bracket boundaries matters because they determine how much a taxpayer can convert before bumping into the next rate. The IRS set those boundaries for tax year 2026 in an Internal Revenue Bulletin that contains the inflation-adjusted amounts for standard deductions, rate thresholds, and related items. The agency also published a separate newsroom summary noting that the 2026 adjustments incorporate statutory amendments from the One, Big, Beautiful Bill, the tax legislation enacted earlier this year. Those amendments preserved the lower individual rate structure that had been scheduled to expire, which means the 10, 12, 22, 24, 32, 35, and 37 percent brackets remain in place for 2026 rather than reverting to the higher pre-2018 schedule.
That legislative outcome is central to the conversion calculus. Had Congress allowed the prior rate structure to return, the 12 percent bracket would have collapsed back into a 15 percent bracket, and the 22 and 24 percent brackets would have merged into a 25 percent bracket. Filers who convert now are locking in rates that could still change in future legislation, but for 2026 the numbers are settled. The individual rate structure is codified under Section 1 of the Internal Revenue Code, and the inflation-adjusted thresholds published in the IRS bulletin apply to taxable years beginning in calendar year 2026.
A Congressional Research Service primer on traditional and Roth IRAs notes that conversions tend to be most advantageous precisely when a taxpayer’s rate is temporarily low. The nonpartisan report, cataloged as RL34397, explains that the lifetime benefit of a Roth conversion depends on whether the tax rate paid at conversion is lower than the rate that would apply to future withdrawals. A year of reduced income is the clearest scenario in which that condition holds.
Testing whether a single-year conversion beats a multi-year spread
One question that surfaces repeatedly in retirement planning is whether a taxpayer should convert a large sum all at once during a low-income year or spread smaller conversions across several years. The logic behind spreading is that it avoids pushing too much income into a higher bracket in any single year. But when income has already fallen sharply, the unused space in the lower brackets can be substantial, and waiting means converting in years when earnings may have recovered.
The hypothesis that a same-year conversion outperforms a three-year spread rests on two conditions: first, that the taxpayer’s income is far enough below normal that they can fill most of a low bracket with converted dollars; and second, that their income is likely to rebound, pushing future conversions into higher brackets. In that situation, front-loading the conversion allows more of the pretax balance to be taxed at the temporarily depressed rate, even if a portion of the one-time conversion creeps into the next bracket.
Consider a simplified example. A married couple typically reports $180,000 of taxable income, placing them solidly in the mid-range brackets. A job loss and a gap between positions drive their 2025 taxable income down to $40,000. Based on the IRS 2026 schedules, they can see precisely how much additional income they can recognize before hitting each higher bracket. If the 12 percent bracket for their filing status tops out at a level well above $40,000, they may be able to convert $30,000, $40,000, or more while still paying only 12 percent on those dollars. Waiting to spread the same total conversion over the next three years, when their income is expected to return to $180,000, would likely subject most of those converted dollars to the 22 or 24 percent brackets instead.
There are cases where a multi-year spread still makes sense. If the low-income year is only modestly below normal, or if the desired conversion amount is large enough that a one-time move would push the taxpayer deep into a higher bracket, spacing out the conversions can keep each year’s marginal rate in check. Similarly, taxpayers approaching retirement might anticipate several consecutive years of relatively low income before Social Security and required minimum distributions begin, allowing them to convert in stages while staying within the same bracket.
Practical guardrails for low-income-year conversions
Even when a low-income year makes a Roth conversion attractive on paper, several practical constraints should shape the decision and the size of the move. First, the tax bill itself must be payable from funds outside the IRA. Using IRA dollars to cover the additional tax undercuts the benefit of the conversion and, for those under age 59½, can trigger early distribution penalties on the withdrawn amount.
Second, large conversions can have collateral effects beyond the income tax brackets. Additional taxable income may increase Medicare premiums in future years, reduce eligibility for certain credits, or cause more Social Security benefits to become taxable. A low-income year blunts some of those impacts, but it does not eliminate them. Running projections that incorporate these secondary consequences is essential before finalizing a conversion amount.
Third, timing within the calendar year matters. Because the tax treatment is locked in for the year of conversion, taxpayers who wait until late December have less room to adjust if they receive unexpected income, such as a bonus, capital gains distribution, or business windfall. Executing a partial conversion earlier in the year and leaving room to top up later, once income is clearer, can provide flexibility while still capturing the low bracket.
A narrow window with known rates
The unusual feature of the current environment is that taxpayers can see the 2026 brackets in advance and know that, under the One, Big, Beautiful Bill, the present rate structure will still be in place. For households whose 2025 income is temporarily depressed, this clarity allows them to compare the tax cost of converting now with the cost of waiting at least a year. If the analysis shows that most future withdrawals would occur in equal or higher brackets, a low-income year conversion becomes a powerful tool.
Ultimately, the decision is less about predicting long-term tax law than about recognizing a temporary, quantifiable gap between today’s income and a taxpayer’s usual level. When such a gap appears, and when cash is available to pay the resulting tax, moving traditional IRA dollars into a Roth while the brackets are known and favorable can permanently shift future growth out of the federal tax system. For many households, that makes a low-income year too valuable an opportunity to ignore.
Free tool for readers: Built for Americans 55 to 80: a free, plain-English retirement check. See your Retirement Safety Score — your 0–100 number and a few steps — in about five minutes, no account needed.
