Consider a 65-year-old single filer who retired in January 2026, has not yet claimed Social Security, and is living off savings. Her modified adjusted gross income for the year will land around $40,000. She wants to convert $30,000 from her traditional IRA to a Roth. Combined MAGI: $70,000. That keeps her under the $75,000 phaseout threshold for the new senior bonus deduction, meaning she claims the full $6,000 break, pays federal tax on the conversion at a blended rate well below 22%, and starts the Roth’s tax-free growth clock years before required minimum distributions would have forced the money out at potentially higher rates.
Now change one variable. She waits until age 68. By then, Social Security benefits and a part-time consulting contract have pushed her baseline MAGI to $65,000. The same $30,000 conversion lifts her to $95,000, which is $20,000 above the phaseout threshold. At the statutory reduction rate of 6% per excess dollar, she loses $1,200 of the deduction. Wait a few more years, and the deduction disappears entirely. The math punishes delay, and the provision itself expires after 2028.
What the law actually provides
The senior bonus deduction was created by the One Big Beautiful Bill Act, signed into law in 2025. It amended Internal Revenue Code Section 151 to add a temporary above-the-line deduction for taxpayers aged 65 and older. The maximum is $4,000 per eligible individual. For filers 78 and older, the maximum rises to $6,000. Married couples filing jointly can claim the deduction for each qualifying spouse, up to $8,000 or $12,000 depending on age.
The deduction applies for tax years 2025 through 2028, giving eligible filers at most four filing seasons before the provision sunsets. As of June 2026, the first returns using the deduction have already been filed, and the second filing season is less than seven months away.
The phaseout is where planning gets critical. Under the statute’s text, the deduction begins to shrink once MAGI exceeds $75,000 for single filers or $150,000 for joint filers. The reduction rate is 6% of every dollar above those thresholds. A single filer at $85,000 loses $600 (6% of the $10,000 excess). At $175,000, the full $6,000 deduction for an older filer is gone. For a married couple filing jointly, the deduction disappears entirely at $350,000.
Because this is above-the-line, it reduces adjusted gross income before the standard or itemized deduction is applied. That ripple effect matters more than the face value suggests. A lower AGI can reduce the taxable portion of Social Security benefits under the IRS Publication 915 formula, help avoid Medicare’s Income-Related Monthly Adjustment Amount surcharges, and preserve eligibility for other income-sensitive credits. For retirees clustered near those thresholds, the downstream savings can exceed the deduction itself.
Why Roth conversion timing changes the outcome
The detail that catches people off guard: a Roth conversion adds the entire converted amount to MAGI in the year it occurs. The conversion itself can push a filer past the $75,000 threshold and erode the very deduction they planned around.
That makes the years between retirement and Social Security claiming especially valuable. A retiree who has stopped working, has no pension, and has deferred Social Security may have a MAGI gap, sometimes called the “retirement sweet spot,” where taxable income is unusually low. Converting traditional IRA dollars during that gap accomplishes two things at once: it captures the senior bonus deduction at or near its maximum, and it shifts money into a Roth where future growth and withdrawals are tax-free under current law.
Required minimum distributions add pressure from the other direction. Under the SECURE 2.0 Act, RMDs begin at age 73 for those born between 1951 and 1959, and at age 75 for those born in 1960 or later. Once RMDs start, they raise MAGI automatically every year and cannot be deferred. A taxpayer who converts a meaningful portion of a traditional IRA balance at 65 reduces the account value that generates those forced distributions later. That creates a double benefit: a larger deduction now and smaller taxable RMDs in the future.
Because the deduction expires after 2028, each lost year of eligibility cannot be recovered. A person who turned 65 in 2025 has four potential filing seasons to coordinate conversions with the deduction. Someone who turns 65 in 2028 gets exactly one shot. That asymmetry can meaningfully change lifetime tax outcomes, particularly for retirees holding six-figure pre-tax balances they want to spread across lower brackets over time.
How to claim the deduction on a tax return
The deduction is reported as an adjustment to income on Schedule 1 of Form 1040 or 1040-SR. Taxpayers do not need to itemize. The IRS incorporated the new line into updated forms and instructions for the 2025 tax year.
Filers who prepare returns themselves will need to calculate the phaseout manually: subtract the applicable threshold ($75,000 for singles, $150,000 for joint filers) from MAGI, multiply the excess by 0.06, and reduce the maximum deduction by that amount. If the result hits zero, no deduction remains.
Married couples where only one spouse is 65 or older should pay close attention. The law allows the deduction per eligible individual, so a couple with one qualifying spouse can claim $4,000 (or $6,000 if that spouse is 78 or older), not the full joint maximum. But the phaseout still uses combined MAGI, which can accelerate the reduction for higher-income households. Coordinating which spouse executes a Roth conversion, and in which year, can help keep joint MAGI within the most favorable range.
IRMAA and state taxes add layers of complexity
Medicare’s IRMAA surcharges present a separate timing concern. IRMAA uses MAGI from two years prior, so a Roth conversion executed in 2026 affects 2028 Medicare premiums. The Centers for Medicare & Medicaid Services publishes updated IRMAA brackets annually. For 2025, the first surcharge threshold for single filers is $106,000 of MAGI; crossing it adds $73.90 per month to the standard Part B premium, or roughly $887 per year. Higher brackets carry steeper penalties. A retiree who converts aggressively in one year to capture the deduction could face elevated Part B and Part D premiums 24 months later. Running the numbers on both the deduction benefit and the IRMAA exposure before converting is not optional.
On the state side, the federal deduction does not automatically carry over to state returns. States that decouple from federal above-the-line adjustments may not recognize the senior bonus deduction at all, meaning a filer could claim the $6,000 federally but owe state tax as if it did not exist. Retirees in states with their own income taxes should verify whether their state has adopted the provision before building it into a multi-year plan. A state tax professional or the state revenue department’s conformity guidance is the most reliable source for that answer.
Building a year-by-year conversion map through 2028
Actual uptake of the deduction paired with Roth conversions will depend heavily on awareness. The provision is new, the interaction with conversion income is not intuitive, and many retirees filing 2025 returns discovered the deduction only when their tax preparer flagged it.
Future tax rates remain an open question. A retiree who expects lower brackets later may see less urgency to accelerate income now, while one who views the temporary $6,000 or $12,000 offset as a rare discount on conversion taxes will want to act before 2028. The possibility that Congress could extend the deduction past its sunset adds another variable, but planning around legislation that does not yet exist is a gamble, not a strategy.
The practical first step: map out expected MAGI for each remaining year from 2026 through 2028. Layer in Social Security start dates, pension income, investment gains, and planned Roth conversion amounts. Test how each scenario interacts with the 6% phaseout, IRMAA brackets, and the Social Security taxation thresholds in IRS Publication 915. With only a few filing seasons left before the deduction sunsets, the window to act is measured in months, not years. A single consultation with a tax professional who can model these overlapping thresholds is likely to pay for itself several times over.
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
