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 lands 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.
The math is uncomfortable: $2.84 million divided by 26.5 equals $107,170. That is the forced withdrawal in year one, taxed as ordinary income whether the retiree spends a dollar of it or not.
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 §63(f)) and taxable income lands near $110,270, squarely inside the 24% bracket. The One Big Beautiful Bill Act also introduced a new $6,000 senior deduction for 2025 through 2028, but it phases out at 6% for every dollar of MAGI above $75,000 for single filers, so a retiree with income above $128,000 sees only a partial benefit.
Federal tax in year one alone runs $19,000 to $21,000. That ignores IRMAA. In 2026, the first Medicare surcharge threshold sits at $109,000 MAGI for single filers. Once income clears that threshold, Part B and Part D premiums jump by hundreds of dollars per month. 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.
Why It Compounds Every Year
The divisor shrinks as the retiree ages. At 75 it is 24.6. At 80, 20.2. At 85, 16.0. At 90, 12.2. A smaller divisor against a balance still compounding near market returns means the forced withdrawal grows in both nominal and real terms. 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.
Persistent inflation compounds the problem further. Nominal RMDs rise alongside a growing account balance, but bracket thresholds adjust more slowly than a portfolio growing at market rates, quietly pushing more income into higher brackets each year.
Four Levers That Actually Move the Number
- 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, lowering every future RMD permanently. With the 10-year Treasury near 4%, conversions also lock in today’s rates against future bracket creep.
- Qualified Charitable Distributions after 70.5. 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. For charitably inclined retirees, this is the cleanest RMD offset the tax code allows, and it became even more valuable under the One Big Beautiful Bill Act because a QCD bypasses the new 0.5% AGI floor that now limits ordinary itemized charitable deductions.
- A Qualified Longevity Annuity Contract. A QLAC lets you 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. It shrinks the divisor problem and hedges longevity risk in a single move.
- 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.
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 article was updated to reflect the correct 2026 standard deduction for a single filer age 65 or older ($18,150, not the previously stated $16,550), which adjusts the taxable income estimate accordingly. The updated 2026 IRMAA threshold of $109,000 for single filers, the current QCD limit of $111,000, and the OBBBA’s new $6,000 senior deduction (available 2025 through 2028, subject to a phase-out above $75,000 MAGI) were also added as relevant context.
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