RMD Age 73 vs. 75: The $1M Traditional IRA Owner’s Distribution Delay Math

Which RMD age applies to you: the birth-year lookup

SECURE 2.0 Act § 107 splits retirees into two cohorts based on birth year. This is not optional, not electable, and not something your custodian will remind you about until it’s almost too late:

Born in 1959? Your first RMD is due by December 31, 2032 (the year you turn 73). Born in 1960? You get two extra years — first RMD not due until 2035 (the year you turn 75). Those two years are worth more than most people realize, because they expand the Roth conversion window before forced distributions begin.

Year-by-year RMD math on a $1M Traditional IRA

The IRS Uniform Lifetime Table (Pub 590-B, Table III) assigns a divisor for each age. Your RMD equals the prior-year-end account balance divided by that divisor. Here’s the math on a $1,000,000 balance, assuming 5% annual growth and that each year’s RMD is the only withdrawal:

Source: IRS Pub 590-B, Table III (Uniform Lifetime Table). Divisors from the 2024-updated table currently in effect.

The pattern: even at 5% growth, the account barely shrinks because early RMDs don’t keep pace with returns. By age 80, you’re forced to take $51,350/year — and the balance hasn’t meaningfully declined. This is the RMD ratchet: the divisor drops faster than the balance, so distributions escalate every year. By age 85 (divisor 16.0), a $1M account at 5% growth forces distributions above $65,000/year.

The bracket math: where RMDs push you

RMD income stacks on top of everything else. For 2026, the federal brackets for a single filer (after the $15,750 standard deduction) are:

A single retiree with $36,000 in Social Security (85% taxable = $30,600) and a $20,000 pension has $50,600 of gross income before the RMD. After the $15,750 standard deduction, taxable income is $34,850 — comfortably in the 12% bracket. Now add the $37,736 RMD: taxable income jumps to $72,586, pushing $24,111 into the 22% bracket. That’s $2,411 more in federal tax than if the same income had stayed in the 12% bracket.

By age 80, when the RMD hits $51,350, the same retiree’s taxable income reaches $86,200 — deep into the 22% bracket and approaching the 24% threshold. And this ignores state income tax, which 41 states impose on IRA distributions.

The IRMAA surcharge trap: RMDs that cost you $4,440/year in Medicare

Medicare Part B and Part D premiums are income-tested. The Income-Related Monthly Adjustment Amount (IRMAA) uses your MAGI from two years prior — so your 2026 RMD affects your 2028 Medicare premiums. The first IRMAA tier (2026 thresholds, based on 2024 MAGI):

At the first surcharge tier, Part B premium jumps from $185/month to $259/month — an extra $74/month ($888/year) per person. For a married couple, that’s $1,776/year. Hit the second tier ($129K–$161K single) and it climbs to $370/month — $4,440/year extra per couple.

Back to our single retiree: $36,000 SS + $20,000 pension + $37,736 RMD = $93,736 MAGI. Just under the $103,000 threshold. But by age 76, when the RMD hits $43,317, total MAGI reaches $99,317 — and by age 77 ($45,061 RMD), MAGI is $101,061. One more year of market growth and the account crosses $103K. The Part B surcharge kicks in. This is the part most retirees don’t model until the Social Security Administration sends the IRMAA notice — two years too late to fix it.

The Roth conversion gap: the two years you can’t get back

Here’s where the age-73-vs.-75 distinction creates real money. If you retire at 65 and delay Social Security to 70, you have a multi-year window where taxable income drops to nearly zero — typically ages 65 to 72 (or 74 if your RMD age is 75). During this window, you can fill low brackets with Roth conversions at bargain tax rates.

Born 1959 (RMD at 73): gap window is roughly ages 65–72 = 7 years of Roth conversion space.

Born 1960 (RMD at 75): gap window extends to ages 65–74 = 9 years of Roth conversion space.

Two extra years of filling the 12% bracket ($48,475 for single) with Roth conversions means roughly $97,000 more converted at 12% instead of 22%+ later. The bracket arbitrage on that $97,000: approximately $9,700 in lifetime federal tax savings — and every dollar converted eliminates that dollar from future RMD calculations permanently.

Worked example: Denver retiree, born 1960, $1.2M in Traditional IRA

A Denver single filer retires at 64, begins Social Security at 70 ($38,400/yr). Between ages 65 and 69, her only income is a small pension of $12,000/yr.

Total converted in the gap: $340,300 at a blended ~12% rate. If she had been born in 1959 (RMD at 73), she’d lose ages 73–74 — $39,170 less converted at 12%, costing her ~$3,917 in bracket arbitrage and leaving those dollars to be forced out as RMDs at 22%+.

The conversion also shrinks her IRA balance from $1.2M to roughly $860K by age 75, which reduces her first RMD from $48,780 (on $1.2M) to $34,959 (on $860K). Lower RMDs mean lower MAGI, lower bracket exposure, and lower IRMAA risk — for life.

The April 1 first-RMD delay: why doubling up costs more than you save

The IRS lets you delay your first RMD until April 1 of the year after you turn 73 (or 75). But you still owe the second RMD by December 31 of that same year. That means two RMDs in one tax year.

On a $1M IRA at age 73 (divisor 26.5) and 74 (divisor 25.5, on a slightly grown balance):

• First RMD (for age 73, taken by April 1 of age-74 year): $37,736
• Second RMD (for age 74, due Dec 31 of same year): ~$39,623
• Total taxable income from RMDs that year: $77,359

For the single retiree with $50,600 of other income, doubling up pushes taxable income (after the standard deduction) from $34,850 to $112,209 — well into the 24% bracket at $103,351. The extra $8,859 above $103,350 is taxed at 24% instead of 22%. And the $112,209 MAGI blows past the $103,000 IRMAA threshold, triggering Part B surcharges of $888/year for 2028.

Delaying cost this retiree ~$1,665 in extra tax + $888 in IRMAA surcharges = $2,553 — to gain what? One year of continued tax-deferred growth on $37,736, worth roughly $1,887 at 5% return. Net loss: ~$666. The delay rarely pays.

Qualified charitable distributions: the $105,000 RMD offset

If you’re 70½ or older and charitably inclined, a qualified charitable distribution (QCD) is the cleanest RMD strategy available. Under IRC § 408(d)(8), you can direct up to $105,000 per person per year (2026, indexed for inflation) from your Traditional IRA directly to a qualified charity. The QCD:

• Satisfies your RMD for the year (if QCD ≥ RMD amount)
• Excluded from taxable income entirely — it never hits your 1040
• Reduces your AGI, which lowers IRMAA exposure, Social Security taxation, and net investment income tax thresholds

A $37,736 QCD that satisfies the full RMD at age 73 keeps $37,736 off the tax return. For a single filer in the 22% bracket, that’s $8,302 of federal tax saved — plus potential IRMAA avoidance worth $888+/year.

The QCD beats the alternative of taking the RMD in cash and donating separately, even if you itemize. Why? The cash-donation route still increases AGI (the income appears, even though the deduction offsets it on Schedule A). Higher AGI means higher IRMAA exposure, more Social Security subject to the 85% inclusion formula, and a higher floor for medical expense deductions (7.5% of AGI). The QCD bypasses all of it.

Limitation: QCDs cannot go to donor-advised funds (DAFs) or private foundations. Only public charities (501(c)(3) organizations that are not supporting organizations) qualify. And if you made deductible IRA contributions after age 70½, those reduce your QCD exclusion dollar-for-dollar.

Inherited IRA timing: why the original owner’s RMD start date matters

Under the SECURE Act 10-year rule (IRC § 401(a)(9)(H) and 2024 final regulations), the original IRA owner’s RMD status at death changes the beneficiary’s obligations:

This distinction makes the owner’s RMD start date an estate planning lever. If a 72-year-old with a $1M IRA (born 1959, RMD age 73) dies before taking the first RMD, her children inherit with no annual distribution requirement — they have full flexibility to time distributions across 10 years to manage bracket exposure. If she dies at 74 (after starting RMDs), the children must take annual distributions based on their own life expectancy, reducing planning flexibility.

For the born-1960+ cohort (RMD at 75), death before age 75 gives beneficiaries even more flexibility — two additional years where the estate plan benefits from the “before RBD” treatment.

The Roth-conversion-then-QCD playbook for $1M+ IRA owners

The most effective strategy combines both tools in sequence:

Phase 1 (ages 65–72 or 74): aggressively Roth-convert during the gap years. Fill the 12% bracket every year. If your other income is low enough, fill the 22% bracket too — it’s still cheaper than the 24%+ bracket RMDs will force later. Target: reduce the Traditional IRA balance by 25–40% before RMDs begin.

Phase 2 (age 73 or 75 onward): use QCDs to satisfy all or part of the RMD. If you’d normally give $20K–$40K/year to charity, redirect those gifts from cash to QCDs. You lose the itemized deduction but gain the AGI reduction — which is worth more for most retirees facing IRMAA, Social Security taxation, and bracket creep.

The combined effect: a $1.2M IRA reduced to $860K through gap-year conversions produces an age-75 RMD of ~$34,959. A $34,959 QCD to the retiree’s church and alma mater satisfies the entire RMD with $0 of taxable income. No bracket creep. No IRMAA hit. No Social Security taxation increase. The Roth account grows tax-free with no RMDs, and the charitable giving was happening anyway — just through a more tax-efficient channel.

The penalty for getting this wrong

Miss an RMD entirely? Under SECURE 2.0, the excise tax is 25% of the amount not withdrawn (down from the prior 50%). On a $37,736 RMD, that’s $9,434. If you correct the error within the IRS correction window (generally the end of the second tax year following the year the RMD was due), the penalty drops to 10% ($3,774). File Form 5329.

But the bigger penalty is the one that doesn’t show up on a tax form: the retiree who never models the Required Beginning Date math and lets a $1M+ IRA compound untouched until forced distributions push them into the 24% bracket with IRMAA surcharges — paying 35%+ effective rate on money that could have been converted at 12% a decade earlier. That’s not a penalty. It’s a planning failure worth $50,000–$100,000+ over a retirement.

Action steps by birth year

Born 1951–1959 (RMD at 73): If you haven’t started RMDs yet, you’re either already taking them or approaching the deadline. Do not delay the first RMD to April 1 unless your income will be materially lower next year. Model the double-RMD year against IRMAA tiers. If you’re charitably inclined, set up QCDs now — your custodian (Fidelity, Schwab, Vanguard) can process them directly.

Born 1960–1965 (RMD at 75, currently ages 61–66): You have the longest gap window. If you’ve retired or plan to retire before 70, model a Roth conversion ladder starting immediately. Every year of 12% conversions between now and age 74 shrinks your future RMD base. This is the single most underused strategy in retirement planning — and the window closes permanently when RMDs begin.

Born 1966+ (RMD at 75, currently under 60): You have decades before RMDs. The priority now is contribution strategy — Roth 401(k) contributions in the 22% bracket or below lock in the tax rate and eliminate those dollars from future RMDs entirely. If your employer offers both Traditional and Roth 401(k) buckets, split contributions based on your current marginal rate vs. projected retirement rate.