Skip to navigationSkip to main contentSkip to right columnADVERTISEMENTGerelyn TerzoTue, June 23, 2026 at 8:02 PM GMT+2 4 min readQuick ReadA Roth conversion can simultaneously trigger ordinary income tax, erase the $6,000 senior deduction, and push up to 85% of Social Security into taxable income.The senior bonus deduction phases out starting at $75,000 MAGI for singles and $150,000 for couples, making conversion size critical for retirees 65 and older.Converting smaller IRA amounts across multiple years, staying below MAGI phaseout ceilings, avoids the tax trap better than a single large December conversion.A recent study identified one single habit that doubled Americans' retirement savings and moved retirement from dream, to reality. Read more here.A 68-year-old retiree collecting Social Security ran a Roth conversion to shrink required minimum distributions (RMDs) waiting at 73. The logic was reasonable: move traditional IRA money now, pay tax at today's rates, and defuse the tax torpedo later. What he did not see coming was that the conversion cost him three different ways in a single year, including the brand-new $6,000 senior bonus deduction that had been heroically keeping his Social Security from being taxed.JU.STOCKER / Shutterstock.comVariations of this scenario show up routinely in retirement forums. Someone in their late 60s converts a chunk of their IRA, feels good about it in December, then watches their tax preparer wince in April. The conversion did exactly what the brochures said. It also pulled levers nobody mentioned.The deduction that disappears as your income risesThe senior bonus deduction is new and temporary. Under the One Big Beautiful Bill, it runs for tax years 2025 through 2028 and gives anyone age 65 or older an extra $6,000 deduction, or $12,000 for a couple where both qualify. It lowers taxable income, which can keep more of a retiree's Social Security off the tax return entirely.The catch is the phaseout. The deduction starts shrinking once modified adjusted gross income (MAGI) crosses $75,000 for a single filer or $150,000 for a couple, and it disappears entirely at higher MAGI levels. Inside the phaseout, the deduction is clawed back at a fixed 6% rate, applied separately to each spouse's $6,000 on a joint return.Read: