A 67-Year-Old With $2 Million in a 401(k) Discovers RMDs Will Trigger a $400,000 Tax Bill

The retiree who built a $2 million traditional 401(k) by age 67 did everything right. Maxed contributions for decades. Captured the employer match. Stayed invested through every selloff. Now, at 67 with $25,000 in Social Security already claimed and no Roth assets, the plan looks obvious: let the 401(k) keep compounding until required minimum distributions kick in at 73. That decision quietly hands the IRS a six-figure bill the retiree never agreed to.

What $2 Million Becomes by Age 73

Compound $2 million at 6% for six years and the balance reaches roughly $2.84 million. That growth looks like a win, but the IRS has been waiting for it. Under SECURE 2.0, the first RMD arrives at age 73 for anyone born between 1951 and 1959. The IRS Uniform Lifetime Table divisor at 73 is 26.5, per IRS Publication 590-B, which means the prior year-end account balance gets divided by that figure to produce the mandatory withdrawal. The divisors in the current table have been in effect since 2022 under Treasury Decision T.D. 9930, and the IRS has not announced a revision for 2026.

The math is uncomfortable: $2.84 million divided by 26.5 equals roughly $107,170. That is the forced withdrawal in year one, taxed as ordinary income whether the retiree spends a dollar of it or not. One timing trap worth flagging: the IRS allows a first-time RMD to be delayed to April 1 of the following year. Taking that delay means two RMDs land in the same calendar year, stacking taxable income in a single filing and potentially pushing the retiree into a higher bracket or over the Medicare surcharge threshold in one jump.

How the RMD Stacks With Social Security

The RMD lands on top of Social Security. With $25,000 in benefits, the income stack pushes 85% of Social Security, or $21,250, into taxable territory. Combined gross taxable income reaches $128,420. Subtract the $18,150 standard deduction available to a single filer age 65 or older in 2026 (the $16,100 base plus a $2,050 age add-on under IRC Section 63(f)) and taxable income lands near $110,270, squarely inside the 24% bracket.

The One Big Beautiful Bill Act introduced a new $6,000 senior deduction for tax years 2025 through 2028, available to filers 65 and older whether they itemize or take the standard deduction. For single filers, it phases out at 6 cents for every dollar of MAGI above $75,000 and disappears entirely at $175,000. A retiree projecting $128,000 in income sees only a partial benefit, roughly $2,820, because the deduction is reduced by about $3,180 from the phase-out math. That partial offset is real, but it does not fundamentally change the bracket picture.

Federal tax in year one alone runs $19,000 to $21,000 before factoring in IRMAA. In 2026, the first Medicare surcharge threshold sits at $109,000 MAGI for single filers. The standard Part B premium is $202.90 per month, but once income clears that threshold, total Part B costs climb from $284.10 to $689.90 per month depending on income tier, while Part D surcharges add $14.50 to $91.00 per month on top of plan premiums. Because IRMAA uses a two-year lookback tied to the prior-prior-year tax return, a 73-year-old’s first large RMD raises Medicare premiums at 75. The surcharge also works as a cliff: crossing the threshold by even one dollar triggers the full additional cost for the entire year.

Why It Compounds Every Year

The divisor shrinks as the retiree ages. At 75 it falls to 24.6. At 80 it is 20.2. At 85 it drops to 16.0, and at 90 to 12.2. A smaller divisor applied against a balance still growing at market rates means the forced withdrawal expands in both nominal and real terms each year. Cumulative RMD-driven federal tax over a 20-year retirement exceeds $400,000, before state tax, before IRMAA, and before the widow’s penalty that hits a surviving spouse who files single on the same income stack. Roughly 12 million Americans aged 73 and older face this challenge annually, and most encounter it without a plan in place.

Persistent inflation deepens the problem. Nominal RMDs rise alongside a growing account balance, but tax bracket thresholds adjust more slowly than a portfolio compounding at market rates. That mismatch quietly pushes more income into higher brackets year after year, even when the retiree’s actual spending stays flat.

Four Levers That Actually Move the Number

1. Bracket-filling Roth conversions between 67 and 73. Converting enough each year to fill the 22% or 24% bracket without spilling into the next one gives six years of disciplined action that can shrink the traditional balance by hundreds of thousands, permanently lowering every future RMD. With the 10-year Treasury near 4%, conversions also lock in today’s rates against future bracket creep.
2. Qualified Charitable Distributions after 70½. A QCD sends IRA dollars directly to a qualified charity, counts toward the RMD, and never enters AGI. The 2026 QCD limit is $111,000 per person, up from $108,000 in 2025. One important caveat: QCDs apply only to traditional IRAs, not directly to a 401(k). A retiree with funds in a 401(k) who wants to use this strategy should first roll the balance into a traditional IRA. The OBBBA changes the comparative math for charitable giving. Non-itemizers can deduct up to $1,000 in cash charitable gifts, but that cap is modest. Itemizers face a new 0.5% AGI floor on donations and a cap limiting deduction value to 35 cents on the dollar. A QCD sidesteps both restrictions entirely because it is an income exclusion, not a deduction, and the AGI reduction also feeds back into lower IRMAA exposure two years forward. For charitably inclined retirees, it remains the cleanest RMD offset the tax code allows.
3. A Qualified Longevity Annuity Contract. A QLAC lets a retiree carve up to $210,000 of a 401(k) or IRA balance out of the RMD calculation entirely, deferring income to as late as age 85. SECURE 2.0 simplified the rules by eliminating the old 25% limit and replacing it with a flat dollar cap that adjusts for inflation. The result is a product that shrinks the divisor problem and hedges longevity risk simultaneously.
4. Spousal sequencing for married couples. The widow’s penalty turns a joint return into a single return overnight, often at the same income level. Coordinating which spouse converts, which claims Social Security first, and which account passes to the survivor can flatten the post-death tax cliff considerably. A plan that looks manageable on a joint return can become punishing once the surviving spouse files single on the same income stack.

What to Do This Quarter

Run your own version of the math. Take your current 401(k) balance, compound it at your expected return to age 73, divide by 26.5, and stack the result on top of Social Security and any pension. If the projected income clears the first IRMAA threshold of $109,000 for single filers, the Medicare surcharge alone justifies engaging a fee-only CPA or advisor who models multi-year conversions. Pull the IRS Uniform Lifetime Table from Publication 590-B and verify the divisor at every age from 73 to 90. Keep in mind that those born in 1960 or later face a starting RMD age of 75 rather than 73, which shifts the planning window but does not eliminate the underlying problem. The retiree who waits until 72 to start planning has already surrendered most of the available savings.

Editor’s note: This pass added the April 1 first-RMD delay warning and the double-RMD stacking risk, the standard Part B premium of $202.90 and the Part D surcharge range of $14.50 to $91.00 per month, and the clarification that the OBBBA senior deduction is available to both itemizers and standard-deduction filers with a worked example of the partial phase-out at $128,000 MAGI. The 2026 QCD limit of $111,000 and the IRMAA cliff language were also sharpened.

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