How Long Will My Money Last?
How many years your savings last if you take the same amount out each month.
Good to know. Take a little less in the bad years and the savings can last decades longer.
Not financial advice. Uses only the numbers and rates you enter — no live data.
How it works
In plain words
Each month the savings grow by the return and the withdrawal comes out. Once a year the withdrawal rises with inflation, so it keeps its buying power. The count stops when the money runs out. Taking out only the return after inflation leaves the savings’ buying power intact, so that amount lasts for good.
The formula
Each month: savings = savings × (1 + i) − withdrawal Each year: withdrawal = withdrawal × (1 + inflation) Lasts for good: savings × (return − inflation, as a real rate) ÷ 12
Worked example
Taking 2,500 a month from 500,000, rising with 2.5% inflation, at a 5% return: the money lasts 21 years 9 months. That first year is a 6% withdrawal rate.
Sources
- Bengen, “Determining Withdrawal Rates Using Historical Data”, Journal of Financial Planning, 1994 The origin of the 4% rule.
- Cooley, Hubbard and Walz, “Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable”, AAII Journal, 1998 The “Trinity study” of withdrawal rates over 15 to 30 years.
- Brealey, Myers and Allen, Principles of Corporate Finance, chapter 2 The standard formulas for loan payments, compounding and present value, the same as a spreadsheet’s PMT and FV.
Sources checked September 29, 2026. 5 automated tests check its answers on every change.
About this calculator
Once you stop working, the question turns around: not how much will I have, but how long will it last? This calculator takes your savings, what you take out each month and what the money earns, and counts the years until it runs out.
The withdrawals rise with inflation once a year, so they keep buying the same things. That is the honest way to plan: 2,500 a month today will need to be about 3,200 in ten years at 2.5% inflation. Leave inflation at 0 if your withdrawals stay flat.
The line “most you can take without running out” is the return after inflation, paid out monthly. Taking only that keeps the savings’ buying power intact forever, which suits anyone who wants to leave something behind. Anything above it slowly eats into the savings.
Real markets don’t deliver a steady return. A few bad years at the start of retirement, when the savings are largest, can shorten how long they last even if the average return is the same. That is why many people start with a withdrawal rate of 4% or less, keep a cash buffer, and take a little less after a bad year.
Questions people ask
How long will 500,000 last?
Taking 2,500 a month rising with 2.5% inflation, at a 5% return, about 21 years and 9 months. At 2,000 a month, about 29 years and 7 months.
How much can I take out and never run out?
About the return after inflation. At a 5% return and 2.5% inflation, roughly 2.4% of the savings a year, rising with inflation.
What is a safe withdrawal rate?
The 4% rule suggests starting at 4% of your savings in the first year, then raising it with inflation, for a retirement of about 30 years.
Does this include tax?
No. Withdrawals from pensions and retirement accounts are often taxed, so the amount you can spend may be lower.