Quick Answer
Quick Answer: A required minimum distribution is your prior year-end balance divided by a distribution-period factor from the IRS Uniform Lifetime Table: RMD = balance ÷ distribution period. For a 75-year-old with a $500,000 balance, the factor is 24.6, so the engine returns an RMD of $20,325.20. Because the factor shrinks every year, the required amount climbs as you age even if your balance stays flat. Miss it and the SECURE 2.0 excise tax is 25% of the shortfall -- $5,081.30 in this case. This page shows the complete math behind every number our calculator produces.
Key Takeaways
- The engine uses two inputs -- your prior year-end account balance and your age this year
- It divides the balance by a distribution-period factor looked up from the IRS Uniform Lifetime Table (Pub. 590-B Table III)
- The factor falls each year, so a steady balance produces a rising RMD over time
- Under SECURE 2.0, RMDs start at age 73 (born 1951-1959) or 75 (born 1960+)
- Missing an RMD triggers a 25% excise tax, reduced to 10% if corrected within the IRS window
Required Minimum Distributions in Plain English
For decades the government let you defer taxes on money in a Traditional IRA or 401(k). A required minimum distribution is how it eventually collects: once you reach your starting age, you must pull a minimum amount out of the account each year so it can be taxed.
The math is a single division. The IRS publishes a table that translates your age into a "distribution period" -- roughly an estimate of your remaining life expectancy in years. You divide your account balance by that number:
- Take your account balance as of December 31 of the prior year.
- Look up the distribution-period factor for your age this year.
- Divide the balance by the factor -- that is your RMD.
Because the factor gets smaller every year (a 73-year-old divides by 26.5, a 90-year-old by 12.2), you are required to withdraw a larger share of the account as you age. The IRS required minimum distributions page(opens in new tab) is the authoritative reference for these rules.
The Mathematical Formula
Here is the exact formula used by our RMD Calculator:
RMD = accountBalance ÷ distributionPeriod
where distributionPeriod is the factor the engine looks up for your age in the IRS Uniform Lifetime Table:
distributionPeriod = UniformLifetimeTable[ ownerAge ]
The engine also reports the excise tax you would owe by skipping the distribution:
penaltyIfMissed = RMD × 0.25
Three rules the engine applies exactly:
- Prior year-end balance: the balance used is always the value on December 31 of the previous year, not today's balance.
- Age flooring: a fractional age is floored to a whole number before the table lookup (Pub. 590-B uses integer ages).
- Zero balance: a $0 balance returns a $0 RMD, while still reporting the distribution period for transparency.
Variable Definitions
| Variable | Meaning | Units / How to Enter | Example (age 75, $500,000) |
|---|---|---|---|
| accountBalance | Prior year-end (Dec 31) account balance | USD | $500,000 |
| ownerAge | Account owner's age this calendar year | Whole years (73 – 120) | 75 |
| distributionPeriod | Uniform Lifetime Table factor for that age | Years (from Pub. 590-B Table III) | 24.6 |
| RMD | Required minimum distribution | balance ÷ distributionPeriod | $20,325.20 |
| penaltyIfMissed | SECURE 2.0 excise tax if skipped | RMD × 25% | $5,081.30 |
Valid Input Ranges
Our calculation engine accepts a prior year-end balance from $0 to $100,000,000 and an owner age from 73 to 120 (the SECURE 2.0 starting age and the top of the Uniform Lifetime Table). These bounds match the engine exactly.
Worked Example: Age 75, $500,000 Balance
This section walks through every step using a common retiree case. You can follow along with a standard calculator and verify the result against our RMD Calculator.
Step 1: Take the Prior Year-End Balance
- Balance on December 31 last year = $500,000
Step 2: Look Up the Distribution Period
Find the owner's age in the IRS Uniform Lifetime Table.
- Owner age this year = 75
- distributionPeriod = 24.6 (Pub. 590-B Table III)
Step 3: Divide to Get the RMD
- RMD = $500,000 ÷ 24.6
- RMD = $20,325.20 (rounded to the cent)
Step 4: Compute the Missed-RMD Penalty
- penaltyIfMissed = $20,325.20 × 25%
- penaltyIfMissed = $5,081.30
Read together: this retiree must withdraw at least $20,325.20 from the account this year -- about 4.07% of the balance. Skipping it entirely would cost $5,081.30 in excise tax (reduced to $2,032.52 if corrected within the IRS window). Every figure above was produced by the calculator's engine with inputs owner age = 75, account balance = $500,000 (verified July 5, 2026).
How Age Changes the Required Amount
Age is the lever that makes RMDs climb over time. The table below holds the balance fixed at $500,000 and varies only the owner's age, so you can see the distribution-period factor shrink and the required amount grow. Every row was computed by the engine.
| Age | Distribution Period | RMD on $500,000 | 25% Penalty if Missed |
|---|---|---|---|
| 73 (starting age) | 26.5 | $18,867.92 | $4,716.98 |
| 75 | 24.6 | $20,325.20 | $5,081.30 |
| 80 | 20.2 | $24,752.48 | $6,188.12 |
| 85 | 16.0 | $31,250.00 | $7,812.50 |
| 90 | 12.2 | $40,983.61 | $10,245.90 |
| 95 | 8.9 | $56,179.78 | $14,044.95 |
On the same $500,000, the required withdrawal more than doubles between age 73 and age 90 -- from $18,867.92 to $40,983.61 -- purely because the divisor falls from 26.5 to 12.2. In practice the balance also changes each year, so retirees usually recompute the RMD annually with the new December 31 balance and the new age.
Balance Scales the RMD Directly
Holding age 75 fixed (factor 24.6), the RMD is simply proportional to the balance: the engine returns $10,162.60 on $250,000, $20,325.20 on $500,000, $30,487.80 on $750,000, and $40,650.41 on $1,000,000. Double the balance, double the RMD.
The Uniform Lifetime Table and SECURE 2.0 Rules
Two pieces of IRS machinery sit behind every RMD: the table that supplies the divisor, and the SECURE 2.0 rules that set when RMDs begin and what missing one costs.
Uniform Lifetime Table (selected ages)
This is the post-2022 Pub. 590-B Table III the engine uses. It applies to most owners taking RMDs from their own accounts.
| Age | Distribution Period | Age | Distribution Period |
|---|---|---|---|
| 73 | 26.5 | 90 | 12.2 |
| 75 | 24.6 | 95 | 8.9 |
| 80 | 20.2 | 100 | 6.4 |
| 85 | 16.0 | 105 | 4.6 |
SECURE 2.0: Starting Age and Penalty
The SECURE 2.0 Act reshaped two RMD rules the engine reflects:
- Starting age tiers — born 1951-1959, RMDs start at 73; born 1960 or later, they start at 75; born 1950 or earlier, the prior age-70.5 / 72 rules applied.
- Reduced excise tax — the penalty for a missed RMD dropped from 50% to 25% (SECURE 2.0 §302), and falls to 10% if you take the shortfall and file the correction within the IRS window (generally two years).
The engine implements the single-year Uniform Lifetime path only. The Joint Life Expectancy Table -- used when your sole beneficiary is a spouse more than 10 years younger -- and inherited-IRA rules are separate; see our inherited IRA RMD rules guide for those.
Data Sources and Methodology Notes
Our RMD Calculator applies the Uniform Lifetime Table and SECURE 2.0 rules documented above. The engine carries full precision through the division and rounds the RMD and penalty to the cent.
Calculation Engine
The same distribution logic runs in the browser and in our public calculator API / MCP server (tool: rmd_distribution_amount — full input/output schema in the API reference), so a result is identical wherever you access it. The engine returns the RMD amount, the distribution period, the table used, and the missed-RMD penalty. As a reproducibility check, the worked example and every table figure on this page were generated by that engine (verified July 5, 2026).
Reference Data
- The distribution-period factors come from the IRS Publication 590-B Uniform Lifetime Table (Table III, post-2022 version)(opens in new tab).
- The starting-age tiers and the reduced excise tax are set by the SECURE 2.0 Act, summarized on the IRS RMD page(opens in new tab).
Assumptions and Limitations
- This tool computes a single-year RMD. For year-by-year projections, run the RMD calculator with each year's projected balance and age.
- Only the Uniform Lifetime Table is implemented. The Joint Life Expectancy Table (sole-beneficiary spouse 10+ years younger) and inherited-IRA schedules are out of scope.
- The balance used is the prior December 31 value; adjustments for certain rollovers or recharacterizations are not modeled.
- RMDs are ordinary income in the year taken; this tool reports the required amount, not the tax you will owe on it.
Frequently Asked Questions
The RMD is your prior year-end account balance divided by a distribution-period factor from the IRS Uniform Lifetime Table (Pub. 590-B Table III). For a 75-year-old with a $500,000 balance, the factor is 24.6, so the engine returns an RMD of $20,325.20. The factor shrinks each year, which is why the required amount rises as you age even if the balance holds steady.
For age 75 the IRS Uniform Lifetime Table gives a distribution period of 24.6 years. You divide the prior year-end balance by 24.6 to get the RMD. Nearby factors are 26.5 at age 73, 20.2 at age 80, and 16.0 at age 85 -- the factor falls each year, so a fixed balance produces a larger required distribution over time.
Under SECURE 2.0, the RMD starting age is 73 for people born between 1951 and 1959, and rises to 75 for those born in 1960 or later. People born in 1950 or earlier were already subject to the prior age-70.5 / 72 rules. The calculator applies the Uniform Lifetime Table from the year you reach your starting age.
SECURE 2.0 set the missed-RMD excise tax at 25% of the amount you failed to withdraw, down from 50% before 2023. It drops to 10% if you correct the shortfall within the IRS correction window (generally two years). For a $20,325.20 RMD, the engine reports a 25% penalty of $5,081.30 if it is missed entirely.
No. This methodology and the rmd_distribution_amount engine use only the Uniform Lifetime Table, which covers most account owners taking RMDs from their own retirement accounts. The Joint Life Expectancy Table (used when a sole-beneficiary spouse is more than 10 years younger) and inherited-IRA rules are separate; for those situations see our inherited IRA RMD rules guide.
Sources
Important Disclaimer
Disclaimer: This content is for educational and informational purposes only and does not constitute financial, tax, or legal advice. Individual circumstances vary, and you should consult with a qualified tax or financial professional before taking or skipping a distribution. RMD rules, starting ages, and penalties are set by the IRS and can change; the figures here reflect the SECURE 2.0 rules and the post-2022 Uniform Lifetime Table current for 2026. While we strive for accuracy, laws and regulations change over time. Data current as of July 2026.
Content reviewed by the Digital Calculator Team. Learn more about our accuracy standards.