When Do RMDs Start? Age 73 or 75 and the April 1 Trap

Margaret turns 73 in November 2026. She is a single filer in Ohio with a $1,000,000 traditional IRA, $32,000 of annual Social Security, and a $42,000 pension. Her first required minimum distribution is roughly $37,736 (her prior-year-end balance divided by the Uniform Lifetime divisor of 26.5). The IRS gives her a choice: take it by December 31, 2026, or delay it to April 1, 2027. Delaying sounds harmless — it is the most expensive mistake on this page. If she waits, her 2027 RMD still comes due December 31, 2027, and she takes two RMDs in one year: about $75,000 of forced income that pushes her into the 22% bracket, makes 85% of her Social Security taxable, and lands an IRMAA Medicare surcharge in 2029. Taking the first RMD on time in 2026 avoids all of it.

The starting age: read your birth year, not a single number

There is no universal RMD age anymore. SECURE 2.0 §107 (signed into law at the end of 2022) replaced the old age 72 rule with a two-tier schedule keyed entirely to the year you were born:

Notice there is no age-74 cohort. If you were born in 1959 you start at 73; cross into 1960 and you skip straight to 75, gaining two extra years of tax-deferred compounding and Roth-conversion runway. That one-year birthdate line is worth real money — the 73-vs-75 cohort math is its own decision.

The April 1 grace period — and why it is a trap

Your required beginning date is April 1 of the year after you reach your RMD age. That is the one and only date the IRS lets you push your first RMD past December 31. Every subsequent RMD is due by December 31 of its own year. Here is the catch that costs retirees thousands: the April 1 extension moves only the first distribution. The second year’s RMD does not move with it.

1. You turn 73 in 2026. Your 2026 RMD (~$37,736) is normally due December 31, 2026.
2. You elect the grace period and defer it to April 1, 2027.
3. Your 2027 RMD is still due December 31, 2027 — roughly $38,500 (a slightly smaller divisor of 25.5 applied to the new prior-year balance).
4. Both land in calendar year 2027: about $75,000 of forced taxable income stacked into one tax return.

The grace period is genuinely useful in exactly one scenario: the year you turn 73 your income is unusually high (a property sale, a final big bonus, exercised options), and the following year it drops. Then deferring shifts the first RMD into a lower-bracket year. For everyone whose income is flat or rising, the on-time first RMD almost always wins.

The math on a $1M IRA: take it now vs. double up

Margaret’s prior-year-end IRA balance is $1,000,000. The Uniform Lifetime Table (IRS Pub. 590-B, Table III) sets the divisor at 26.5 at age 73, so $1,000,000 ÷ 26.5 = $37,736. Compare her two paths:

The 2026 federal brackets for a single filer put the 22% band at $48,476–$103,350 and the 24% band at $103,351–$197,300. By spreading the two RMDs across 2026 and 2027 instead of stacking them, Margaret keeps her 2027 taxable income out of the 24% bracket entirely and stays under the first IRMAA threshold ($103,000 MAGI single, based on 2024 income for 2026 premiums). The on-time choice is not exotic planning — it is simply refusing to volunteer for a double-income year.

Which accounts require RMDs — and which do not

RMDs apply to pre-tax retirement money. The rule of thumb: if you got a deduction going in, the IRS wants its tax eventually, so it forces withdrawals. Roth dollars were already taxed, so most are exempt for the original owner.

One aggregation trap worth flagging: IRAs can be pooled, so you compute the RMD on each and take the combined total from any single IRA. Employer 401(k) accounts cannot — if you have two old 401(k)s, each must distribute its own RMD separately. Rolling old 401(k)s into one IRA before your RMD year simplifies this dramatically.

The missed-RMD penalty: 25%, or 10% if you move fast

Skipping an RMD used to carry a brutal 50% excise tax. SECURE 2.0 §302 cut that to 25% of the shortfall — and to 10% if you correct it within the two-year correction window and file Form 5329 reporting the make-up distribution. On Margaret’s $37,736 RMD, a complete miss is a $9,434 penalty at 25%, dropping to $3,774 at 10% if she catches it promptly. The IRS will also generally waive the penalty entirely if you show the shortfall was due to reasonable error and you have taken steps to remedy it (attach a statement to Form 5329). The lesson: a missed RMD is fixable, but only if you act inside the window.

How the RMD amount is calculated — and why it grows every year

Your RMD is not a flat percentage. Each year you divide your prior-year-end balance by a divisor from the IRS Uniform Lifetime Table (Pub. 590-B, Table III). The divisor shrinks as you age, so the percentage you must withdraw climbs every year even if your balance stays flat:

Two wrinkles change the math. If your sole beneficiary is a spouse more than 10 years younger, you use the more generous Joint Life and Last Survivor Table instead, lowering the RMD. And a QLAC (qualified longevity annuity contract) lets you move up to $210,000 (2026 limit, SECURE 2.0 §202) out of the balance used to compute RMDs — the premium is excluded under Treas. Reg. §1.401(a)(9)-6, deferring that slice of income until as late as age 85.

The still-working exception that delays your 401(k) RMD

One legitimate way to push past 73 or 75: the still-working exception. If you are still employed at the company that sponsors your 401(k), are not a 5%-or-greater owner, and your plan allows it, you can delay RMDs from that employer’s plan until April 1 of the year after you retire. Critical limits:

• It applies only to the current employer’s plan — not to your IRAs, and not to 401(k)s from former employers, which all start on the normal 73/75 schedule.
• It does not apply if you own more than 5% of the business sponsoring the plan.
• One planning move: roll old 401(k)s into your active employer’s plan (a “reverse rollover”) before your RMD year so the still-working exception shelters that money too — but this only works for 401(k) dollars, never IRA dollars.

What most people miss: the RMD bill is really a Social Security and Medicare bill

Retirees fixate on the income tax on the RMD itself and ignore the two larger downstream hits:

• Social Security taxation. Under IRC §86, once your combined income clears $34,000 (single) or $44,000 (MFJ), up to 85% of your Social Security becomes taxable — and those 1983 thresholds are not inflation-indexed, so a $75K double-up year buries you well past them. A modest RMD can convert previously tax-free Social Security into taxable income, a hidden marginal-rate spike.
• IRMAA Medicare surcharge. Under Social Security Act §1839(i) (administered by CMS), your Part B and Part D premiums are set by your MAGI from two years prior. A double-RMD year in 2027 can raise your 2029 premiums from the $185.00/month base into a higher tier — an extra $74–$444 per month per person, for a full year, off a one-time income spike.
• The widow’s penalty. When one spouse dies, the survivor files single — same RMDs, half the brackets, half the IRMAA thresholds. RMDs that were comfortable as MFJ can become punishing the year filing status changes.

This is why pre-RMD years (the 65–73 gap) are the most valuable planning window in retirement: Roth conversions and qualified charitable distributions done before RMDs begin shrink the future required withdrawal and defuse all three downstream effects.

Two levers that shrink the RMD before it starts

You cannot avoid RMDs on pre-tax money, but you can shrink the balance they are calculated against — which lowers the dollar amount, the Social Security drag, and the IRMAA risk for the rest of your life.

• Roth conversions in the 65–73 gap. Every dollar you convert from a traditional IRA to a Roth before 73 is a dollar that never produces an RMD (Roth IRAs have no lifetime RMD). Converting $80,000/year for eight years — while filling up the 22% and 24% brackets but staying under the IRMAA tier — can move roughly $640,000 out of the RMD base, cutting Margaret’s eventual age-73 RMD by about $24,000/year. The conversion deadline is December 31 of each tax year, and conversions cannot be undone (TCJA eliminated recharacterization).
• Qualified charitable distributions (QCDs). Once you turn 70½, you can send up to $108,000 (2026 limit) per year directly from your IRA to charity. A QCD counts toward your RMD but is excluded from taxable income — better than taking the RMD and donating, because it never hits your adjusted gross income, so it does not inflate Social Security taxation or IRMAA. For a charitably inclined retiree, a $37,736 RMD satisfied entirely by QCD is taxed at $0.

The two levers stack: convert to Roth in the low-income years before 70½, then use QCDs to satisfy the RMDs you cannot convert away. Together they can keep a seven-figure IRA owner out of the top IRMAA tiers permanently.

The decision lever

The single choice that determines whether RMDs cost you an extra bracket is what you do with your first one. Default to taking it on time, in the year you turn 73 or 75 — never reflexively defer to April 1, because that converts one manageable withdrawal into a two-RMD income spike that taxes your Social Security and surcharges your Medicare. Only use the April 1 grace period when the year you turn 73/75 is an unusually high-income year and the next year drops. Then, in the runway before your RMD age, model whether Roth conversions in the 65–73 gap shrink the $37,736 number enough to keep you under the IRMAA and 85%-Social-Security thresholds for the next decade.