Retirement withdrawal calculator
See how long a balance may last under an entered plan.
- Formula and assumptions shown
- Table and CSV export
- Runs in your browser
How it works
Each modeled month applies the entered return, then withdraws the planned amount up to the funds available. The annual withdrawal increase becomes an effective monthly growth rate. After the balance is depleted, the table continues through the chosen horizon and reports the unfunded portion of each planned withdrawal.
Each month: available balance = prior balance × (1 + annual return ÷ 12); actual withdrawal = min(planned withdrawal, available balance); next planned withdrawal = prior plan × (1 + annual increase)^(1/12).
The horizon is deliberately bounded and the result is a stress-test scenario. It is not a safe-withdrawal rule or a prediction of market performance.
Assumptions
- Returns are applied monthly before each withdrawal; the withdrawal is capped at the available balance.
- The annual return and withdrawal-increase assumptions remain constant; withdrawal growth is converted to an effective monthly rate.
- The schedule continues through the selected horizon after depletion and shows unfunded planned withdrawals.
- Taxes, fees, sequence-of-returns risk, benefits, and account rules are excluded.
Worked example
$10,000 with $1,000 monthly withdrawals
With a 0% return, no withdrawal increase, and a two-year horizon, the portfolio funds 10 monthly withdrawals and reaches $0 in month 10. The remaining 14 planned withdrawals total $14,000 and are shown as unfunded shortfalls.
Step by step
- Horizon and planned withdrawals. A two-year horizon is 2 × 12 = 24 months. With no withdrawal increase, the plan calls for 24 × $1,000 = $24,000.
- Monthly return. At a 0% return, no interest is added, so each month the balance simply falls by the $1,000 withdrawal.
- Depletion. $10,000 ÷ $1,000 = 10 withdrawals. The balance reaches $0 in month 10, so the headline reads 10 months and actual withdrawals total $10,000.
- Unfunded withdrawals. Months 11 through 24 are 14 planned withdrawals with nothing to fund them: 14 × $1,000 = $14,000 unfunded, and the ending portfolio is $0.
How to read your result
The headline, Portfolio lasts, is the month in which the balance reaches zero, or The full horizon when money remains at the end. Ending portfolio is the balance left at the horizon. First planned monthly withdrawal repeats the starting amount; later withdrawals grow by the increase you enter, converted to a monthly rate (2.5% a year is about 0.206% a month). Actual withdrawals is the total paid out, and Unfunded planned withdrawals is the total the plan asked for but the portfolio could not pay.
The table shows each month’s balance, return, planned and actual withdrawal, and shortfall, and it continues after depletion so the size of the gap stays visible. With the default inputs the planned withdrawal has grown from $4,000 to $8,321.49 by month 357, the month the money runs out, which shows how much a steady inflation increase adds over three decades.
Every month earns the same return. Real portfolios rise and fall, and the order matters: losses in the early years of withdrawals shrink the balance that later gains can work on, so the same average return can run out sooner. Taxes are not deducted, so treat withdrawals from pre-tax accounts as amounts before tax. Social Security, pensions, and other income are outside the model.
What changes the result most
- Return assumption
- With the defaults ($1,000,000, $4,000 a month rising 2.5% a year, 5% return), the money lasts 357 months (29 years 9 months). At a 4% return it lasts 302 months, and at 3% it lasts 266 months.
- Withdrawal increase
- Holding withdrawals flat at $4,000 lets the portfolio last the full 30 years with $1,138,709.77 left, while a 3.5% annual increase shortens it to 304 months.
- Starting withdrawal
- Starting at $5,000 a month instead of $4,000 shortens the runway from 357 to 261 months, and unfunded planned withdrawals rise to $942,834.91.
Questions
Does this prove my money will last?
No. It is a deterministic scenario with entered assumptions. Real returns vary and the order of good and bad years can materially change outcomes.
Can withdrawals rise with inflation?
Yes. The model converts the annual increase you enter into an effective monthly rate and applies it to each next planned withdrawal.
Does it include Social Security or a pension?
No. Include only the balance and withdrawals modeled here. Other income should be considered separately.
How long will my money last in retirement?
It depends mainly on the balance, how much is withdrawn, how fast withdrawals grow, and the return earned. Enter those four and the calculator reports the month the balance runs out, or that it lasts the full horizon. Because real returns vary from year to year, it helps to run a lower return as well; with the defaults, dropping the return from 5% to 3% shortens the runway from 357 months to 266.
How long will $1 million last in retirement?
Under the default assumptions, $1,000,000 with withdrawals starting at $4,000 a month and rising 2.5% a year, earning 5%, lasts 357 months, just short of 30 years. With withdrawals held at $4,000 it lasts the full 30 years with $1,138,709.77 left, and at $5,000 a month rising 2.5% it lasts 261 months. The answer changes with each assumption, taxes, and the order of market returns.
What is a safe withdrawal rate?
The term usually refers to research on historical market returns, starting with William Bengen’s 1994 study, which found that withdrawing 4% of a portfolio in the first year and raising it with inflation would have lasted at least 30 years in every historical period he tested for a U.S. stock and bond mix. That is a finding about past data, not a guarantee. Longer retirements, different investments, fees, and future returns can all change the outcome, and this calculator treats the withdrawal amount as an input rather than calling any rate safe.
More in Retirement
- Retirement savings
- Retirement withdrawal
- FIRE
Sources
These references explain the concepts behind the calculation. They do not endorse this site. Estimates leave out any cost or condition you did not enter.