Required minimum distributions used to be simple: turn 70½, start withdrawing. SECURE 2.0 split that single age into a sliding scale tied to your birth year — and in 2026, a meaningful slice of retirees are still calculating their first RMD off the wrong starting age. The IRS penalty for getting it wrong runs as high as 25% of the amount that should have come out.
The Three Tiers, Set by Birth Year
The current rules, codified by the SECURE Act of 2019 and amended by SECURE 2.0 in 2022, create three groups:
- Born before 1951: RMDs already underway. Original starting ages of 70½ or 72 applied; these retirees are well past their first distribution year.
- Born 1951–1959: RMDs begin in the year you turn 73. This is the active group for most new 2026 RMDs.
- Born in 1960 or later: RMDs begin in the year you turn 75.
The age-75 trigger does not phase in until 2033 (when the first 1960-born savers turn 73 under the old rules). For 2026, the practical line is age 73 — but anyone born in late 1953 needs to know they hit the rule this year, not next.
The Deadlines That Catch People
The IRS gives first-timers a one-time grace period: your first RMD can be deferred until April 1 of the year after you reach RMD age. Every subsequent RMD is due by December 31 of that calendar year.
That grace period is a trap as often as a gift. Deferring your first RMD into the following April means you take two RMDs in the same tax year — the delayed one plus the current-year distribution. For a retiree on the edge of an IRMAA Medicare premium tier or a Social Security taxation threshold, doubling up taxable income in a single year can cost more than the deferral saves.
What the Penalty Actually Looks Like
SECURE 2.0 cut the missed-RMD excise tax from 50% to 25%, and to 10% if the shortfall is corrected within a two-year window by taking the distribution and filing IRS Form 5329. The reduced penalty is generous by historical standards, but it still applies to the missed dollar amount, not the tax on it. Miss a $30,000 RMD and the floor is a $3,000 penalty even after a fast correction.
How the Number Is Calculated
Your RMD equals the prior-year December 31 balance of each applicable account divided by the IRS Uniform Lifetime Table factor for your age. A 73-year-old's factor is 26.5, which works out to roughly 3.77% of the account. Spouses more than 10 years younger who are the sole beneficiary can use the Joint Life table for a smaller distribution.
A few quirks worth knowing in 2026:
- Roth 401(k) and Roth 403(b) accounts no longer have lifetime RMDs, effective January 2024 under SECURE 2.0. Roth IRAs were already exempt.
- Each traditional IRA can be aggregated — calculate separately, withdraw from any one. 401(k) accounts cannot — each plan's RMD must come out of that plan.
- Still-working employees can generally delay RMDs from a current employer's 401(k) (but not IRAs or former-employer plans) until retirement, provided they aren't 5%+ owners.
Practical Takeaways
- Confirm your tier in writing. Pull your birth date and the IRS tables side by side. Don't rely on a plan administrator's default — they don't always update for SECURE 2.0 amendments.
- Model the "two-RMD year" before deferring. Run the projected April-of-next-year withdrawal against your tax bracket, IRMAA brackets, and Social Security provisional income before choosing the grace period.
- Consider a Qualified Charitable Distribution. Retirees 70½ and older can send up to $108,000 in 2026 directly from an IRA to charity, satisfying part or all of an RMD without adding to taxable income.
- Set a calendar reminder for December 1. A two-week buffer before the December 31 deadline catches custodian processing delays and avoids the penalty entirely.
- File Form 5329 immediately if you've already missed one. The 10% reduced penalty requires the correction to be timely; waiting compounds the cost.
The age-73-vs-75 split is one of the few SECURE 2.0 changes that demands action from retirees themselves rather than plan sponsors. The dollar value of getting it right — or wrong — sits squarely on the account holder.
Sources: Internal Revenue Service; Charles Schwab; The Motley Fool; Schneider Downs; Fidelity.