How to calculate your RMD: the IRS table, a worked example and the April 1 trap.

A required minimum distribution sounds like something you need an accountant to work out, and the arithmetic is one division. The hard parts are the age it starts, the first-year deadline, and which accounts count. I built a free RMD calculator, and this is how the number is made, with a worked example from its engine and the one first-year trap that catches people.

How is an RMD calculated?

The IRS says an RMD "is calculated for each account by dividing the prior December 31 balance of that IRA or retirement plan account" by a life-expectancy factor (IRS RMD FAQs). For most owners the factor, called the distribution period, comes from the Uniform Lifetime Table (Publication 590-B, Table III, in force since 2022). Three steps:

1. Find the account balance on December 31 of last year.
2. Find the distribution period for the age you reach this year. It is your age at the end of the year, so someone turning 75 in 2035 uses the 75 row all year, even in January.
3. Divide the balance by the period.

The IRS's own example in Publication 590-B is $100,000 at 75, which with a period of 24.6 is $4,065. Scale it to $1,000,000 and the answer is $40,650.41, which is 4.07% of the balance. Because the balance is last year's, you know the amount in January.

At what age do RMDs start?

At 73 for people born 1951 through 1959 and at 75 for people born in 1960 or later, with 72 for people born July 1, 1949 through 1950 and 70½ for those born earlier. People born in 1959 are in a gap in the law between 73 and 75 that the IRS has not settled, and the calculator uses 73. Your first RMD is for the year you reach that age. The key retirement dates calculator and the post on key retirement dates show the year for your birthday, alongside Medicare and Social Security.

What does the IRS table say at each age?

The period shrinks as you age, so the share of the balance you must take grows. For a $1,000,000 balance on December 31 of the year before:

The share more than doubles between 73 and 90 and is about four times as large by 100. The full table is on the RMD calculator, with a CSV.

What does an RMD schedule look like over the years?

The RMD in dollars depends on what the account does. Take someone born June 15, 1960, who has $1,000,000 on December 31, 2034 and whose account grows 5% a year after each RMD. This is an illustration of the arithmetic, not a forecast:

The balance peaks near $1,019,811 at 80, and then the RMDs outrun the growth. The dollar RMD keeps rising, to a peak of $77,030 at 95, because the share rises faster than the balance falls. Over the 26 years from 75 to 100 the RMDs total $1,642,329, and about $388,990 is left at the end of the year the person turns 100. With no growth at all the same account pays $40,650 at 75 and falls to $20,259 at 100, $890,600 in total. Either way, an RMD is a minimum set by age, not a spending plan.

What happens if I wait until April 1 for the first one?

The IRS lets you delay the first RMD, with an example: if you reach age 73 in 2024 you must take your first RMD by April 1, 2025 and the second by December 31, 2025 (IRS RMD FAQs). The first RMD is taxable in the year you take it, so waiting moves it into the second year, where it lands on top of that year's own RMD. For the example above:

Waiting does not change the first RMD, but it makes the second a little larger ($44,303.80 instead of $42,502.83), because the balance on December 31, 2035 has not been reduced by it. The bigger effect is that $84,954 of income lands in one year, which is more than the $42,503 it would have been. That can push income into a higher tax bracket in that year and, because Medicare looks at your income two years back, can raise your Medicare premiums later. Whether it is worth it depends on your other income that year, which is a question for a tax professional.

Which accounts count, and which table applies?

• IRAs combine. Figure each traditional IRA's RMD, add them up, and the IRS says you can take the total "from one or more of the IRAs". A 403(b) contract owner can do the same across 403(b) contracts.
• 401(k) and 457(b) plans do not. The RMD "must be taken separately from each of those plan accounts."
• Roth accounts have none while you live. The IRS says Roth IRA and designated Roth account withdrawals "are not required until after the death of the account owner."
• A qualified charitable distribution can count. From 70½ you can send IRA money straight to a charity and keep it out of taxable income, and it can count toward the year's RMD (IRS).
• A much younger spouse changes the table. If your spouse is your sole beneficiary and is more than 10 years younger than you, the IRS says to use Table II (Joint and Last Survivor), which generally gives a smaller RMD. The calculator uses the Uniform Lifetime Table only. Inherited accounts have their own rules too.

Money moved to a Roth before RMDs start is no longer in the account that is divided, which is why Roth conversions and RMDs are planned together; the Roth conversion calculator shows whether a conversion pays off at your tax rates.

What if I miss an RMD?

The amount you should have taken may be subject to a 25% excise tax, reduced to 10% if you correct it within two years, reported on Form 5329 (Form 5329 instructions). The IRS may waive it for reasonable error if you file Form 5329 with a letter of explanation. Fix it as soon as you find it, and ask a tax professional.

What does the calculator assume, and what does it leave out?

• One balance, one table. It divides the balance you enter by the Uniform Lifetime Table. It does not know your other accounts, a spouse's beneficiary status or a plan's own rules.
• Growth is your assumption. The schedule and the "if you wait" figures use the yearly growth you enter, with each RMD taken at the start of the year. Real timing and returns differ, and this year's RMD does not use growth at all.
• Taxes are not computed. It shows the RMD, not what you will owe on it.
• Birth years from 1943. And the ambiguous 1959 year uses 73.

Does the calculator save my numbers?

No. It runs in your browser. Your date of birth and balance are not sent to us or stored.

How were these numbers calculated?

• Rules: the Uniform Lifetime Table (Publication 590-B, Table III) divides the December 31 balance; the age is the age reached in the year; the starting age comes from the birth date.
• Code: every figure here comes from the same code the calculator is tested against. The distribution periods exist in two independent copies in Runway's engine, one keyed by hand and one parsed from IRS Notice 2022-6, and a test requires them to match; the page's JavaScript is checked against a separate Python version on 10,440 combinations of birth date, balance, year and growth.
• Example: born June 15, 1960, $1,000,000 on December 31, 2034, 5% yearly growth after each RMD taken at the start of the year, ages 75 through 100. Amounts are rounded to the cent where shown to the cent.
• As of: October 26, 2026. The table and rules change rarely, and the sources are linked.

Frequently asked questions

How do I calculate my RMD?

Take your account balance on December 31 of the year before and divide it by the distribution period from the IRS Uniform Lifetime Table for the age you reach during the year. For example, $1,000,000 at age 75 divided by 24.6 is $40,650.41.

What is the RMD on $1 million?

It depends on your age: $37,735.85 at 73, $40,650.41 at 75, $49,504.95 at 80, $62,500.00 at 85 and $81,967.21 at 90, using the IRS Uniform Lifetime Table and a balance of $1,000,000 on December 31 of the year before.

Can I wait until April 1 for my first RMD?

Yes. Your first RMD can be taken as late as April 1 of the year after the year you reach your starting age. The catch is that your RMD for that next year is also due by December 31, so you take two in one year. In the example here that is $40,650.41 plus $44,303.80, $84,954.21 in 2036.

Do I have to take RMDs from a Roth IRA?

Not while you are alive. The IRS says withdrawals from Roth IRAs and designated Roth accounts "are not required until after the death of the account owner." Beneficiaries are subject to RMD rules.

What is the penalty for missing an RMD?

The amount you should have taken may be subject to a 25% excise tax, reduced to 10% if you correct it within two years. You report it on Form 5329, and the IRS may waive it for reasonable error.