Draw a set amount each month and see how long your balance holds out.
A systematic withdrawal calculator shows how long an investment portfolio will last when you draw a fixed amount each month, given an expected return.
A portfolio shrinks as you withdraw but grows as it earns a return, so it lasts far longer when the return offsets the withdrawals. If your withdrawal is below the monthly growth, the balance can last indefinitely; above it, the money depletes over time. The calculator simulates this month by month.
This assumes a steady return, but real markets vary, and a run of poor early returns, sequence risk, can shorten how long money lasts even at the same average. Many retirees stay flexible, trimming withdrawals in down years, and keep a cash buffer. Taxes and inflation also matter, so treat the result as a planning estimate.
It depends on the balance, withdrawal amount, and return. If withdrawals exceed the growth, it depletes over time; below it, it can last indefinitely.
The risk that poor returns early in retirement, while the balance is largest, shorten how long money lasts, even if the average return is fine.
Withdraw less, stay flexible in down years, keep a cash buffer, and use a sustainable withdrawal rate around 4% or lower.
See the exact formula and a worked example on our methodology page.