The RMD bomb: how pre-tax savings become forced income
Every dollar in a traditional IRA or 401(k) carries a deferred tax bill, and the IRS does not wait forever to collect. Required minimum distributions (RMDs) force money out of pre-tax accounts on a schedule — as ordinary, taxable income — whether you need it or not. For diligent savers with large pre-tax balances, that schedule can detonate late in retirement: hence the nickname, the “RMD bomb.”
When RMDs start: ages 73 and 75
The SECURE 2.0 Act made the start age depend on your birth year. If you were born between 1951 and 1959, RMDs begin at age 73. If you were born in 1960 or later, they begin at 75. (Those born in 1950 or earlier fell under the older rules and are already taking them.) Missing an RMD triggers an excise tax of 25% of the shortfall — reduced to 10% if corrected promptly.
How the Uniform Lifetime Table works
Each year’s RMD is your pre-tax balance on December 31 of the prior year, divided by a life-expectancy factor from the IRS Uniform Lifetime Table. The factor shrinks every year, so the required percentage grows: at 73 the divisor is 26.5 (about 3.8% of the balance), at 80 it is 20.2 (about 5.0%), at 85 it is 16.0 (6.25%), and at 90 it is 12.2 (about 8.2%).
A worked example
Suppose you retire with $2 million in pre-tax accounts and it grows faster than you spend it. At 75 (born 1960 or later), the first RMD is $2,000,000 ÷ 24.6 ≈ $81,300 of forced ordinary income — on top of Social Security and anything else. If markets are kind and the balance keeps compounding, the percentage keeps rising too: a balance still worth $2 million at 85 forces out $125,000 that year ($2,000,000 ÷ 16.0). Forced income at that scale can climb the tax brackets, make more of your Social Security taxable, and push you over Medicare IRMAA surcharge thresholds — a cascade the “bomb” label describes.
Two knock-on effects deserve special mention. Medicare’s IRMAA surcharges are keyed to your MAGI from two years earlier, so a spike of forced income at 75 raises both spouses’ Part B and Part D premiums at 77. And the bomb often lands hardest on a surviving spouse: the same RMDs continue, but they are now taxed under the much narrower single-filer brackets — the so-called widow’s penalty. Even after death the deferral bill survives: most non-spouse heirs must empty an inherited pre-tax account within ten years, usually during their own peak earning years, at their marginal rate.
Defusing it
The common levers all move taxable income from the forced years into cheaper voluntary ones. Spending from pre-tax accounts earlier in retirement shrinks the future balance. Roth conversions in low-income years move money somewhere RMDs never reach — Roth IRAs have no lifetime RMDs for the owner.
And once you reach age 70½, qualified charitable distributions (QCDs) let you give directly from an IRA to charity. A QCD counts toward your RMD but is excluded from income entirely — often better than deducting a cash gift, because it lowers AGI and MAGI rather than itemized deductions. The annual cap was set at $100,000 per person and is now indexed for inflation.
Try it in Deorbit Plan
The simulator applies the SECURE 2.0 start ages and the full Uniform Lifetime Table automatically — check the year-by-year detail table on the Results dashboard to watch RMDs appear on the median path and see what they do to your tax line. To defuse them, set a conversion strategy in the Strategy panel (e.g. Fill bracket (retired years)) and enter an annual amount in Qualified charitable distributions from age 70½; the engine counts QCDs toward the RMD and keeps them out of income, so you can compare lifetime tax with and without them.
Educational content only — not financial, tax, or investment advice.
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