401k RMD Calculator

• How to calculate RMD for a 401k?

  Divide your prior-year-end (December 31) balance by the IRS Uniform Lifetime Table factor for your age. At 73 the factor is 26.5, so a $500,000 balance requires an $18,868 distribution for the year — about 3.8% of the balance. The factor shrinks each year as you age, so the required percentage rises steadily: by 80 the factor of 20.2 forces a $24,752 withdrawal on the same balance, or about 5%. You must take the full amount by December 31, though the very first year allows deferral to April 1. One caveat: each 401k must satisfy its own RMD separately — unlike IRAs, you cannot total them and withdraw from one account — and Roth 401k balances no longer require lifetime RMDs under SECURE 2.0, so only traditional balances count.

• How is RMD calculated for a 401k?

  The formula is: RMD = the December 31 balance of the prior year ÷ your life-expectancy divisor. The divisor comes from the IRS Uniform Lifetime Table and decreases with age, which raises the required percentage every year. For example, a $400,000 balance at age 73 (divisor 26.5) requires about $15,094; the same balance at 75 (divisor 24.6) requires about $16,260. Most account holders use the Uniform Lifetime Table, but a different table applies if your sole beneficiary is a spouse more than 10 years younger. One caveat: the balance used is always the prior year-end figure, not today's, so a market swing during the year does not change the current RMD — and missing the deadline triggers a penalty of 25% of the shortfall, reduced to 10% if corrected promptly.

• How to calculate the required minimum distribution from a 401k?

  Take last year's December 31 ending balance and divide it by the Uniform Lifetime Table divisor for your current age, then repeat the calculation every year with the new balance and new divisor. The result must be withdrawn by December 31 to avoid a penalty (the very first RMD may be delayed to April 1 of the following year). For example, a $600,000 balance at age 74 uses a divisor of 25.5, giving an RMD of about $23,529. Because the divisor falls with age, the required amount rises even if your balance stays flat. One caveat: you can always withdraw more than the RMD, but the excess does not reduce future years' requirements, and each 401k is calculated and satisfied on its own — you cannot aggregate multiple 401k accounts the way IRA rules allow.

• Who calculates the RMD for a 401k — the plan administrator?

  Your plan administrator often calculates and reports your RMD each year, but you are legally responsible for taking the correct amount — if the plan's figure is wrong or you hold multiple accounts, the liability is still yours. It is wise to verify it yourself using your prior-year-end balance and the IRS Uniform Lifetime Table divisor for your age. For example, on a $500,000 balance at 73, divide by 26.5 to confirm the roughly $18,868 figure. If you hold more than one 401k, each plan calculates only its own, and you must take each separately. One caveat: unlike IRAs, 401k RMDs cannot be aggregated and taken from a single account, so relying on one plan's statement can leave another plan's RMD unmet — and missing it triggers a penalty of up to 25% of the shortfall.

• At what age do 401k RMDs start?

  Required minimum distributions start at age 73 for anyone born between 1951 and 1959, and at age 75 for those born in 1960 or later, under the SECURE 2.0 Act. Before the 2022 law the age was 72, and earlier still 70½, so your exact start age depends on your birth year. Your first RMD can be delayed until April 1 of the year after you turn 73 (or 75), but doing so means taking two distributions in that year, which can push you into a higher tax bracket. For example, someone born in 1955 begins at 73; someone born in 1962 waits until 75. One caveat: Roth 401k accounts no longer have lifetime RMDs under SECURE 2.0, so only your traditional 401k balances trigger a required distribution while you are alive.

• What happens if I miss a 401k RMD?

  Missing a required minimum distribution triggers an excise tax of 25% of the amount you failed to withdraw — one of the harshest penalties in the tax code. The good news is SECURE 2.0 cut it from the old 50%, and it drops further to 10% if you correct the shortfall within a two-year window and file the right form. For example, missing a $20,000 RMD exposes you to a $5,000 penalty, or $2,000 if promptly corrected — on top of the ordinary income tax you still owe on the distribution itself. One caveat: the penalty applies per account per year, so overlooking one of several 401k plans is enough to trigger it — the safest approach is to automate the withdrawal each year so the deadline is never missed.

• IRS-accurate formulas

  Uses the current IRS contribution limits, penalty rules and RMD tables — updated for 2026.

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