Required Beginning Date: April 1 of which year?
1 April of the year following the year the applicable age is reached. Not 1 April of that year — a distinction that quietly breaks a lot of software.
| Date of birth | Applicable age | Reaches it in | Required Beginning Date |
|---|---|---|---|
| 15 June 1953 | 73 | 2026 | 1 April 2027 |
| 1 February 1951 | 73 | 2024 | 1 April 2025 |
| 9 August 1960 | 75 | 2035 | 1 April 2036 |
Why the off-by-one matters more than it looks
For a living participant, getting this wrong only mislabels a date. For a deceased participant it changes everything, because "died before the RBD" versus "died on or after the RBD" is the single branch that determines the entire beneficiary rule set — whether annual RMDs are required, whether the 5-year or 10-year rule applies, and which life expectancy is used.
A participant who turns 73 in 2026 and dies in December 2026 died before their RBD, even though they were past the applicable age all year. Software that places the RBD in 2026 will classify that death as post-RBD and produce a materially different schedule.
The two-RMD year
For a participant near a bracket threshold, an IRMAA cliff, or a Social Security taxability threshold, taking the first RMD by 31 December of the first year is often the better outcome. The deferral is an option, not an instruction.
When retirement moves the date
For employer plans only, a participant who is not a 5% owner may defer the RBD to 1 April following the year they actually retire. That is the still-working exception, and it has conditions worth checking.
Check a real case. The calculator applies every rule on this page — SECURE 2.0 applicable ages, the before/after-RBD test, EDB classification and the 2024 final regulations.
Open the RMD calculator