Withdrawal Calculator
Estimate how many months a starting balance lasts with a fixed monthly withdrawal and optional growth rate.
Guide
What is a withdrawal runway estimate?
A withdrawal runway estimate shows how long a balance lasts when you withdraw a fixed amount each month while the remaining balance optionally earns a fixed annual rate.
Formula
Each month, interest = Remaining balance × (Annual rate ÷ 100 ÷ 12). Remaining balance = Remaining balance + Interest − Withdrawal. The schedule repeats until the balance reaches zero. At a zero rate, months = Starting balance ÷ Monthly withdrawal when the division is exact in the simulation.
Worked example
A 1,200 balance with a 100 monthly withdrawal at 0% interest lasts 12 months. Total withdrawn is 1,200 and total interest is zero.
Assumptions and limitations
The Calculator assumes a fixed withdrawal, fixed rate, and no new deposits, fees, or taxes. If the withdrawal does not exceed the first month's interest, the balance never declines and the estimate is rejected.
Common questions
How is this different from the Retirement Calculator?
Retirement projects accumulation and required nest egg. This Tool starts from a balance and spends it down. Can the final month be partial? Yes. The last withdrawal is limited to the remaining balance plus that month's interest.
Methodology
The Calculator simulates month-by-month balances with decimal arithmetic up to 1,200 months and rounds only displayed totals.