A required minimum distribution calculator tells you exactly how much the IRS requires you to withdraw this year from a Traditional IRA, 401(k), or similar pre-tax retirement account β a figure that's easy to get wrong if you're doing the math by hand from the IRS life-expectancy tables.
Arb Digital built this tool because RMD mistakes are expensive and entirely avoidable. Get your age and balance right, apply the correct life-expectancy factor, and the required withdrawal β plus the rough tax bill that comes with it β is a straightforward division problem.
What This RMD Calculator Does
Enter your retirement account balance as of December 31 of last year, your age this year, and whether your spouse is your sole beneficiary and more than 10 years younger than you (a situation that uses a different, more favorable IRS table). The calculator looks up the correct life-expectancy factor and divides your balance by it to produce your required withdrawal for the year, along with the monthly equivalent, the percentage of your balance that represents, and an estimate of the tax you'll owe on it.
The calculation itself is simple arithmetic, but getting the right life-expectancy factor by hand means locating the correct year's IRS table and reading the right row for your exact age β an easy place to make a small error that compounds into a wrong withdrawal amount. This tool keeps both the Uniform Lifetime Table and the Joint Life and Last Survivor Table built in, so switching between them is a single dropdown selection rather than a trip back to the IRS publication every time your situation changes.
A Real-World Example
Say you're 73 with a $500,000 account balance as of last December 31. Using the Uniform Lifetime Table, the factor at 73 is 26.5, so your RMD is $500,000 divided by 26.5, or roughly $18,868 for the year β about $1,572 a month if you spread it evenly, though you're free to take it as a single lump sum or several withdrawals instead. If your spouse were your sole beneficiary and more than 10 years younger, the Joint Life table's larger factor at that age would produce a smaller required withdrawal, since the IRS assumes the money needs to last over both of your combined life expectancies rather than yours alone.
How to Use the RMD Calculator
- Enter your account balance as of December 31 of the prior year. This is the figure your custodian reports and the IRS uses for the calculation β not your current balance.
- Enter your age this year. The life-expectancy factor changes every year as you get older.
- Indicate whether your spouse is your sole beneficiary and more than 10 years younger. This triggers the IRS Joint Life and Last Survivor Table, which produces a smaller required withdrawal.
- Enter your estimated tax rate on the withdrawal, then click Calculate to see your RMD, the factor used, and the estimated tax.
The Formula: The IRS Uniform Lifetime Table
Your RMD is calculated as your prior-year-end account balance divided by a life-expectancy factor published in the IRS Uniform Lifetime Table (used by most account owners), found in IRS Publication 590-B and the RMD topic page. For example, at age 73 the factor is 26.5, meaning you divide your balance by 26.5. As you age, the factor shrinks each year, which increases the percentage of your balance you're required to withdraw β by age 90 the factor drops to around 12.2. This calculator includes a built-in lookup table covering the common ages, and switches to the more generous Joint Life table when your spouse is your sole beneficiary and more than 10 years younger.
RMDs Start at 73 β and the Penalty for Missing One Is Steep
Under current law, RMDs generally begin the year you turn 73. If you fail to withdraw the full required amount by the deadline (typically December 31, with a special extended deadline for your very first RMD), the IRS can assess an excise tax of 25% on the shortfall β though that penalty drops to 10% if you correct the mistake within a defined correction window. Given how large that penalty is compared with ordinary income tax, RMDs are one area of retirement planning where a calendar reminder is genuinely worth setting.
Roth IRAs Have No RMDs for the Original Owner
One reason Roth IRAs are so popular in retirement planning: unlike Traditional IRAs and most 401(k)s, the original account owner never has to take an RMD from a Roth IRA during their lifetime. That means Roth balances can keep compounding tax-free for as long as you like, which is part of why some retirees strategically convert Traditional balances to a Roth over several years β spreading out the tax hit while shrinking the pool of money that will eventually force RMDs. If that's a strategy you're weighing, our Roth Conversion Calculator can help you model it.
Qualified Charitable Distributions Can Offset the Tax
If you're charitably inclined, a Qualified Charitable Distribution (QCD) lets you direct some or all of your RMD β up to an annual limit set by the IRS β straight to a qualifying charity. The amount sent this way counts toward satisfying your RMD but isn't included in your taxable income, which can be a meaningfully more tax-efficient way to give than withdrawing the RMD, paying tax on it, and then donating what's left. It's worth discussing the mechanics and paperwork with your account custodian and a tax professional before year-end.
RMDs From Multiple Accounts
If you hold more than one Traditional IRA, the rules allow you to calculate each account's RMD separately and then withdraw the combined total from any single IRA or any mix of them β you don't have to pull evenly from each one. Workplace plans like 401(k)s work differently: generally, the RMD for each 401(k) must be withdrawn from that specific plan rather than aggregated with your IRAs or with other employer plans. If you have a mix of old 401(k)s and IRAs from different jobs, it's worth mapping out each account's RMD individually before deciding where the withdrawals will actually come from, since getting the source account wrong can still leave a required amount unmet in a specific plan even if your overall total withdrawal looks correct.
Inherited Accounts Follow Different Rules
This calculator is built around RMDs for your own account as the original owner. If you've inherited a retirement account from someone else, the rules are meaningfully different and depend on your relationship to the original owner, whether they had already started RMDs, and rules introduced by the SECURE Act that generally require most non-spouse beneficiaries to empty an inherited account within 10 years. Inherited-account RMDs are one of the more frequently miscalculated areas of retirement planning, so it's worth confirming your specific situation directly against current IRS guidance or with a tax professional rather than assuming the standard owner rules apply.
See what converting pre-tax savings to a Roth could cost now and save later.
Try the Roth Conversion Calculator All Free ToolsHow RMDs Interact With Social Security and Medicare
A large RMD doesn't just raise your income tax bill in isolation β it can also increase how much of your Social Security benefit is taxable, and it can push your income high enough to trigger Medicare's Income-Related Monthly Adjustment Amount (IRMAA), a surcharge added to Medicare Part B and Part D premiums for higher earners. Because IRMAA is based on your tax return from two years prior, an unusually large RMD this year can quietly raise your Medicare premiums two years from now. This ripple effect is one more reason to plan RMDs and any related Roth conversions well before age 73, rather than reacting to the first mandatory withdrawal notice from your custodian.
Common Mistakes to Avoid
- Using the wrong year's balance. The RMD is always based on the account balance as of December 31 of the prior year, not today's balance.
- Missing the deadline. RMDs are generally due December 31 each year, with a special extended deadline only for your very first one.
- Forgetting to aggregate multiple IRAs. You can calculate each IRA's RMD separately but withdraw the total from any combination of them β 401(k) RMDs generally can't be combined the same way.
- Assuming a Roth IRA has an RMD. It doesn't, for the original owner β only inherited Roth IRAs and Roth 401(k)s (pre-2024 rules) had RMD considerations.
- Not planning for the tax hit. RMDs are taxed as ordinary income and can push you into a higher bracket or affect Medicare premium surcharges.
Related Free Tools From Arb Digital
If you're weighing whether to convert pre-tax savings before RMDs kick in, try the Roth Conversion Calculator. Compare account types with the Traditional IRA Calculator and Roth IRA Calculator, or model your workplace savings with the 401k Calculator. For the bigger retirement picture, see our Retirement Calculator, or browse everything on the free online tools hub.
Frequently Asked Questions
Under current IRS rules, required minimum distributions generally begin the year you turn 73.
The IRS can assess an excise tax of up to 25% on the amount you failed to withdraw, reduced to 10% if you correct the shortfall within the IRS correction window.
No. The original owner of a Roth IRA is not required to take RMDs during their lifetime, which is a key advantage over Traditional IRAs and most 401(k)s.
A QCD lets you send some or all of your RMD directly to a qualifying charity, up to an annual IRS limit, without counting that amount as taxable income.
Use your account balance as of December 31 of the previous year, as reported by your account custodian, not your current balance.
Yes. If your spouse is your sole beneficiary and more than 10 years younger, the IRS Joint Life and Last Survivor Table applies, producing a smaller required withdrawal.
This tool provides general estimates for educational purposes only and is not financial, tax, legal, or medical advice. Figures are illustrative; consult a licensed professional for decisions.
