Nobody Warned This 72-Year-Old His First RMD Would Cost an Extra $19,000 in Tax

Meet a 72-year-old single retiree with roughly $1 million in a traditional IRA, another couple hundred thousand in taxable and cash accounts, and about $30,000 a year in Social Security. This spring he modeled his first Required Minimum Distribution and realized his tax bill next year will be roughly $19,000 higher than expected.

This is one of the most common wealth-stage surprises in retirement. Millions of Americans hold most of their savings inside traditional IRAs and 401(k)s. When the RMD switch flips at age 73, forced withdrawals pile on top of Social Security income, and a larger tax bill almost always follows.

At 73, the IRS Uniform Lifetime Table assigns a distribution period of 26.5. Against roughly $1 million in IRA assets, that divisor produces a first-year RMD somewhere in the high $30,000s to low $40,000s, depending on the prior December 31 balance. Stack that withdrawal on top of $30,000 in Social Security plus any interest from CDs or Treasuries, and provisional income blows past the single-filer breakpoints of $25,000 and $34,000. That triggers the second problem: up to 85% of his Social Security becomes taxable income at the same time the RMD itself is fully taxable.

Why the Bracket Math Bites

For a single filer in 2026, the standard deduction is $16,100. The 12% bracket ends at $50,400, and the 22% bracket runs from there to $105,700. Before the RMD, his taxable income sat comfortably in 12% territory. Once the RMD stacks with newly taxable Social Security, his top dollars land firmly in the 22% bracket, costing him the benefit of the lower rates he had been living inside for a decade.

One partial offset is worth knowing: the One Big Beautiful Bill Act created a temporary $6,000 bonus deduction for taxpayers 65 and older, available for tax years 2025 through 2028. That deduction begins to phase out for single filers above $75,000 in modified adjusted gross income, however, and disappears entirely by $175,000. For our retiree, the RMD alone could push MAGI well past the phase-out floor, meaning the deduction shrinks precisely when extra income arrives.

Then add IRMAA surcharges on Medicare Part B and Part D. These surcharges key off modified adjusted gross income and, crucially, use a two-year lookback: your 2024 income is what determines your 2026 premiums. For single filers, the first IRMAA tier kicks in above $109,000 in MAGI and pushes total Part B premiums from the standard $202.90 per month up to $284.10 per month or higher. The true marginal cost of the last dollar of RMD can climb well above 22% once IRMAA is factored in. That compounding effect is how the total extra tax bill reaches the neighborhood of $19,000.

Between age 60 and 72, our retiree had a genuine opportunity: low reported income, no RMDs, and flexibility on when to claim Social Security. That window is prime territory for filling the 12% or even 22% bracket voluntarily by converting traditional IRA dollars to Roth. He missed it because no advisor was at the table and his target-date fund quietly rebalanced without any tax planning attached.

(For readers still inside that window, the Roth window playbook walks through how retirees in their 60s can use low-bracket years before RMDs and Social Security force their hand.)

Two Moves That Still Work at 72

1. Consider a partial Roth conversion this year, before the first RMD arrives. He still has one clean tax year left. Converting enough IRA money to fill the 12% bracket (up to $50,400 of taxable income) shrinks the balance the 26.5 divisor will be applied against next year. Every dollar moved to Roth never generates another RMD. The conversion is itself taxable, but at 12% it is meaningfully cheaper than the 22%-plus blended rate he will otherwise pay for the rest of his life.
2. Qualified Charitable Distributions starting at 73. If he gives to charity regardless, sending money directly from the IRA to a qualified nonprofit satisfies the RMD without adding a dollar to adjusted gross income. That can keep both Social Security taxation and IRMAA in check. For a retiree with a household spending base near $78,500 a year, even modest QCDs can materially shift the tax picture and help preserve eligibility for the new senior deduction.

If you are in this position, start by projecting the year-end IRA balance and running the RMD against the 26.5 divisor. Decide before December 31 whether to execute a bracket-filling Roth conversion. Waiting for the CPA to flag this during tax season is the most common mistake: by then, the conversion window for the year has closed, the RMD is locked in, and the $19,000 bill is effectively unavoidable.

Editor’s note: This article was updated to incorporate the new $6,000 senior deduction introduced by the One Big Beautiful Bill Act (effective tax years 2025 through 2028), which phases out for single filers above $75,000 in MAGI, and to add detail on how IRMAA’s two-year income lookback compounds the RMD tax problem for 2026. The 2026 IRMAA single-filer threshold of $109,000 and the standard Part B premium of $202.90 per month were also confirmed and noted.

Contact [email protected] for any questions or corrections.