Savings Drawdown Calculator
See how long a nest egg lasts if you withdraw a fixed amount each month while the remaining balance keeps earning a return. Useful for planning retirement or any drawdown.
Your details
- Months until depleted
- 285.14
- Total withdrawn
- $855,426.24
Formula
With monthly return r, the balance lasts n = ln(W ÷ (W − B·r)) ÷ ln(1 + r) months, where B is the balance and W the monthly withdrawal. If monthly growth exceeds the withdrawal, the balance never runs out.
How it works
The return on your remaining balance stretches your money far beyond simply dividing the balance by the withdrawal. If your withdrawals stay below what the balance earns, it can last indefinitely — the basis of a sustainable withdrawal rate.
Frequently asked questions
How long will my savings last?⌄
It depends on your balance, how much you withdraw, and the return you keep earning. This calculator solves for the number of months until the balance reaches zero.
What if my withdrawals are small?⌄
If your monthly withdrawal is less than the monthly return the balance earns, your savings grow rather than shrink and can last indefinitely — the calculator flags this.
How does this relate to the 4% rule?⌄
The 4% rule is a rule of thumb for a withdrawal rate likely to last ~30 years. This calculator lets you test any balance, withdrawal, and return directly.
Sources & methodology
Closed-form depletion of a balance under constant monthly withdrawals and a constant return. Excludes taxes, inflation, and variable returns. Not investment advice.
- •Investor.gov — retirement — SEC
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