Retirement Drawdown Calculator
See how long a pot of savings lasts at a given monthly withdrawal and return.
How to use the Retirement Drawdown Calculator
- Enter your current retirement savings.
- Enter how much you plan to withdraw each month.
- Enter the return you expect the remaining balance to earn.
- See how long the money lasts — or whether it lasts indefinitely.
Months = ln(W ÷ (W − P×r)) ÷ ln(1 + r), r monthly return, W withdrawal
About the Retirement Drawdown Calculator
The hardest question in retirement is not how much you have saved but how long it will last once you start spending it. This calculator answers exactly that: it draws your chosen monthly amount from the pot while the remaining balance keeps earning a return, and reports how many years and months pass before it runs dry. If your withdrawals are smaller than the interest the balance earns, it tells you the money lasts indefinitely — the balance is self-sustaining and may even grow.
That crossover point is the insight worth grasping. A pot that earns 5% throws off interest each month; withdraw less than that and you live on the growth, withdraw more and you eat into the capital, with the timeline shortening fast as the gap widens. Small changes to the monthly amount can turn "lasts 40 years" into "lasts 18", which is why the withdrawal rate matters more than almost anything else.
This is a smooth projection at a constant return, so treat it as a guide, not a guarantee. Real markets fall as well as rise — and a bad run early in retirement hurts far more than the same run later — while inflation raises what you need to withdraw and tax reduces what you keep. For the saving phase, use the retirement savings calculator; to see inflation's bite, the inflation calculator.
Frequently asked questions
What does "lasts indefinitely" mean?
It means your monthly withdrawal is less than the interest the balance earns, so you are living off the growth and the capital is not depleted. It assumes a steady return, which real markets do not guarantee.
Should I account for inflation?
Ideally yes. As prices rise you will need to withdraw more to maintain your lifestyle, which shortens how long the money lasts. For a cautious estimate, use a return net of inflation — your real return.
What is a safe withdrawal rate?
A widely cited guide is around 4% of the starting balance per year, adjusted for inflation, but it is only a rule of thumb. Your own safe rate depends on your returns, time horizon and flexibility.