The IRS uses a simple formula: your prior December 31st account balance divided by a life expectancy factor from the IRS Uniform Lifetime Table. The factor decreases each year as you age, meaning RMDs grow as a percentage of your account balance over time.
The RMD Formula
RMD = Prior December 31 Account Balance ÷ IRS Life Expectancy Factor
Example: A 73-year-old with a traditional IRA balance of $500,000 on December 31 of the prior year. The IRS Uniform Lifetime Table factor for age 73 is 26.5.
- ✓ $500,000 ÷ 26.5 = $18,868 RMD for the year
- ✓ At age 80 (factor 20.2): $500K ÷ 20.2 = $24,752
- ✓ At age 85 (factor 16.0): $500K ÷ 16.0 = $31,250
Note that as the factor decreases with age, the required withdrawal as a percentage of your balance increases. For a growing account, RMDs can become very large, potentially pushing you into higher tax brackets and triggering IRMAA Medicare premium surcharges.
Multiple accounts: If you have multiple traditional IRAs, calculate the RMD for each separately, but you can withdraw the total from any one or combination of your IRAs. For 401(k) plans, each plan's RMD must generally be taken from that plan specifically.
Accounts Subject to RMDs
- ✗ Traditional IRA
- ✗ Traditional 401(k) and 403(b)
- ✗ SEP IRA
- ✗ SIMPLE IRA
- ✗ 457(b) (governmental)
- ✓ Roth IRA: NO RMDs during owner's lifetime
- ✓ Roth 401(k) / Roth 403(b): NO RMDs beginning in 2024 (SECURE 2.0)
Exception for active workers: If you are still employed at age 73 and participating in your current employer's 401(k), you may be able to delay RMDs from that plan until you retire. This does not apply to IRAs or 401(k) plans from previous employers.