How Are Required Minimum Distributions Calculated?

To calculate a required minimum distribution, divide the retirement account’s fair market value on December 31 of the prior year by the life expectancy factor that matches your age this year in the appropriate IRS table.¹ That single division gives you the minimum you must withdraw for the year. A 73-year-old with a $500,000 traditional IRA balance divides by 26.5 and gets an RMD of roughly $18,868.

The Two Numbers You Need

The first number is your account’s fair market value as of December 31 of the previous year. Your year-end statement from the custodian shows this figure. If you own more than one account that requires an RMD, you pull the prior-year balance for each one separately.

The second number is a life expectancy factor from an IRS table in Publication 590-B.² The age you use is the age you will reach by December 31 of the distribution year, not your age on the day of the withdrawal.

Divide the balance by the factor. That is the calculation. You can always withdraw more, but withdrawing less exposes you to a penalty.

Which IRS Table Applies to You

Three tables exist, and using the wrong one produces the wrong number.

Uniform Lifetime Table

Most account owners use this table. It applies unless your sole beneficiary is a spouse more than 10 years younger than you.

Joint and Last Survivor Table

You use this table when your spouse is your sole beneficiary and is more than 10 years younger than you.² The factors are larger than those in the Uniform Lifetime Table because they reflect the combined life expectancy of both spouses, so the required withdrawal is smaller.

Single Life Expectancy Table

This table is primarily for beneficiaries who inherit a retirement account and take distributions based on their own life expectancy.² Inherited accounts follow their own set of rules covered further down.

Sample Uniform Lifetime Factors

For most account owners, these are the divisors during the years RMDs commonly begin:

Age 73: 26.5
Age 74: 25.5
Age 75: 24.6
Age 76: 23.7
Age 77: 22.9
Age 78: 22.0
Age 79: 21.1
Age 80: 20.2

The factor shrinks each year, so the RMD grows as a percentage of the balance even when the balance stays flat. A worked example: if your traditional IRA was worth $500,000 on December 31, 2025, and you turn 75 during 2026, you divide $500,000 by 24.6. That produces a 2026 RMD of $20,325.

Calculating RMDs When You Have More Than One Account

You run the formula separately for each account you own. What you can do with those separate results depends on the account type.

Traditional, SEP, and SIMPLE IRAs

Calculate an RMD for each IRA, then add them together. You can take the combined total from any one IRA or split it across several.³

401(k) and 457(b) Plans

No aggregation. If you have multiple 401(k) accounts from former employers, you must calculate each plan’s RMD separately and take it from that specific plan.³

403(b) Plans

These behave like IRAs for aggregation purposes. Add the RMDs across your 403(b) accounts and take the total from any one of them.³

You can never cross account types. An IRA RMD cannot be satisfied from a 401(k), and a 401(k) RMD cannot be satisfied from an IRA, regardless of what aggregation each type allows internally.

Accounts That Don’t Require an RMD Calculation

Roth IRAs require no RMDs during the original owner’s lifetime.⁴ Starting in 2024, Roth 401(k) and Roth 403(b) accounts inside employer plans are also exempt while the account owner is alive.⁵ Beneficiaries who inherit any Roth account still face distribution rules.

There is also a still-working exception for the plan at your current employer. If you participate in your current employer’s 401(k) or similar workplace plan and you do not own 5% or more of the business, you can delay RMDs from that plan until the year you retire.⁵ The exception does not extend to IRAs or to plans left at former employers.

Calculating an RMD on an Inherited Account

Inherited accounts follow a different framework. Whether you owe an annual RMD, and how you calculate it, depends on who you are relative to the deceased owner.

Eligible Designated Beneficiaries

A surviving spouse, a minor child of the account owner, a disabled or chronically ill person, and anyone not more than 10 years younger than the deceased can still stretch distributions over their own life expectancy.⁶ The calculation uses the Single Life Expectancy Table with the beneficiary’s age. A surviving spouse also has the option to roll the account into their own IRA and treat it as their own, which switches the calculation back to the standard owner rules.

The 10-Year Rule for Other Beneficiaries

Most other beneficiaries, such as adult children and siblings, must empty the account by the end of the tenth year following the owner’s death. Whether annual RMDs are also required during those 10 years depends on when the original owner died.⁷

If the owner died on or after their required beginning date, you must take annual RMDs in years one through nine using the Single Life Expectancy Table, and empty whatever remains by the end of year 10. This requirement took effect for 2025.
If the owner died before their required beginning date, no annual RMD is required. You can take distributions on any schedule, as long as the account is empty by the end of year 10.

These rules apply to accounts inherited after 2019. Accounts inherited before 2020 generally still follow the older stretch rules based on the beneficiary’s own life expectancy.⁶

What Happens If You Calculate Wrong

If your withdrawal falls short of the calculated amount, or you skip it entirely, an excise tax of 25% applies to the shortfall.⁵ The penalty drops to 10% if you correct the shortfall within two years.¹

You can also request a full waiver of the penalty by filing IRS Form 5329 with a written explanation showing the shortfall was due to reasonable error and that you are taking steps to fix it.⁸ Enter “RC” and the amount you want waived on the dotted line next to line 54 of the form, then attach your explanation. The IRS reviews each request and notifies you if additional tax is owed.

1
Internal Revenue Service. Retirement Topics – Required Minimum Distributions (RMDs)
2
Internal Revenue Service. Publication 590-B (2025), Distributions From Individual Retirement Arrangements (IRAs)
3
Internal Revenue Service. RMD Comparison Chart (IRAs vs. Defined Contribution Plans)
4
Office of the Law Revision Counsel. 26 USC 408A – Roth IRAs
5
Internal Revenue Service. Retirement Plan and IRA Required Minimum Distributions FAQs
6
Internal Revenue Service. Retirement Topics – Beneficiary
7
Internal Revenue Service. Notice 2024-35 – Certain Required Minimum Distributions for 2024 and 2025
8
Internal Revenue Service. Instructions for Form 5329 (2025)