Savings Withdrawal Duration
Estimate how long a balance lasts with fixed monthly withdrawals.
Your numbers
Withdrawal duration
Withdrawals occur at month end. Rates are constant; taxes, fees and market sequence risk are omitted. Fractional months interpolate the model.
Scenario comparison
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Formula
n=−ln(1−Br/W)/ln(1+r); n=B/W at r=0
Estimate how long a balance lasts with fixed monthly withdrawals.
Worked example
- Starting balance
- 12000
- Monthly withdrawal
- 1000
- Nominal annual return (%)
- 0
- Withdrawal duration
- 12 months
Scope and limitations
Withdrawals occur at month end. Rates are constant; taxes, fees and market sequence risk are omitted. Fractional months interpolate the model.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: 543a931cd4b9 · Example checked: