How an RMD is calculated
Once you reach the RMD start age, you must withdraw a minimum amount from your tax-deferred accounts each year. The amount is simply your prior year-end balance divided by a life-expectancy divisor — the “distribution period” — from the IRS Uniform Lifetime Table. Because that divisor gets smaller each year, the required withdrawal grows as a share of your balance the older you get.
The RMD formula
RMD = Prior year-end balance ÷ Distribution period
At age 73 the divisor is 26.5, so the RMD is about 3.8% of the balance. By age 90 the divisor is 12.2 (≈8.2%), and by 100 it's 6.4 (≈15.6%). The divisors come straight from IRS Publication 590-B, Table III.
Worked example
Take a 73-year-old with $500,000 in a Traditional IRA at the end of last year, paying 22% tax on distributions. Here is the first required withdrawal — and what the whole projection to age 95 adds up to:
| Step | Amount |
|---|---|
| Prior year-end balance (age 73)Traditional IRA / 401(k) value at the end of last year | $500,000 |
| ÷ Distribution period at age 73the divisor from the IRS Uniform Lifetime Table (Publication 590-B, Table III) | 26.5 |
| = First-year RMDabout 3.8% of the balance must come out this year | $18,868 |
| − Estimated tax at 22%RMDs from tax-deferred accounts are ordinary income | $4,151 |
| = After-tax withdrawalwhat actually lands in your pocket at age 73 | $14,717 |
| Total RMDs, ages 73–95assuming 5% annual growth — about $151,541 goes to estimated tax, leaving $537,280 after tax | $688,821 |
Computed with this calculator's default settings and the actual IRS Uniform Lifetime Table — open the tool above and you'll see the same numbers, then adjust the balance, ages, and rates to match your own accounts.
RMDs projected from the real IRS table
- The real IRS table, not a guess. We embed the full Uniform Lifetime Table, so every year's divisor is exact.
- A multi-year projection. Most tools show a single year. We project every RMD from the start age to your end age, so you can see how the required withdrawal rises as the divisor shrinks.
- The tax, estimated. Each distribution is taxable income — we show the estimated tax on every year's RMD and the lifetime total.
- SECURE 2.0, made explicit. RMDs now begin at age 73. We default to it and let you adjust.
Frequently asked questions
What is a required minimum distribution (RMD)?
An RMD is the minimum amount you must withdraw each year from most tax-deferred retirement accounts — Traditional IRAs, 401(k)s, 403(b)s, and similar — once you reach the RMD age. Because the money went in pre-tax and grew tax-deferred, the IRS requires you to start taking it out (and paying income tax on it) so it doesn’t stay sheltered indefinitely. The required amount equals your prior year-end balance divided by a life-expectancy divisor from the IRS Uniform Lifetime Table.
At what age do RMDs start?
Under the SECURE 2.0 Act, RMDs now begin at age 73 for anyone who reaches 73 in 2023 or later (it was 72 before, and 70½ before that). The age is scheduled to rise to 75 in 2033. Your first RMD can be delayed until April 1 of the year after you turn 73, but doing so means taking two distributions in that year. This calculator defaults to the age-73 start.
What is the IRS Uniform Lifetime Table?
It’s the table most account owners use to find their RMD “distribution period” — a life-expectancy divisor that gets smaller each year you age. You divide your prior year-end balance by the divisor for your age to get that year’s RMD. At 73 the divisor is 26.5 (about 3.8% of the balance); by 90 it’s 12.2 (about 8.2%); by 100 it’s 6.4. Because the divisor shrinks, the required withdrawal rises as a share of the account over time. This calculator uses the actual IRS table, not an estimate.
What is the penalty for missing an RMD?
If you don’t take your full RMD by the deadline, the IRS imposes an excise tax on the shortfall. SECURE 2.0 reduced this penalty from 50% to 25%, and to 10% if you correct the mistake promptly (generally within a two-year window) and file the right form. Even with the reduction, missing an RMD is expensive — which is why projecting them ahead matters.
Which accounts require RMDs?
Tax-deferred accounts require RMDs: Traditional IRAs, SEP and SIMPLE IRAs, and most employer plans like 401(k), 403(b), and 457(b) accounts. Roth IRAs do NOT require RMDs during the original owner’s lifetime, and as of 2024 Roth 401(k)s no longer require them during the owner’s lifetime either. Inherited accounts follow separate rules.
Disclaimer: This calculator is for educational purposes only and assumes the IRS Uniform Lifetime Table, which applies to most account owners. A different table (Joint Life and Last Survivor) applies if your sole beneficiary is a spouse more than 10 years younger. Investment returns and tax rates are assumptions, and inherited-account rules differ. This is not tax or financial advice — consult a qualified professional.