Savings Withdrawal Calculator — How Long Will Savings Last?
Plan your drawdown: enter your savings balance, interest rate and either the duration you need or your desired withdrawal amount — the calculator finds the other value and shows the declining balance over time.
Solve for
%
Withdrawal frequency
years
Amount you can withdraw each period until savings are depleted
- 1
Period rate
4% ÷ 12 ÷ 100 = 0.003333 - 2
Number of periods
20 × 12 = 240 - 3
Discount factor
1 − (1 + 0.003333)^−240 = 0.550073Scales the present value annuity to find the equal periodic payment. - 4
Withdrawal per period
100,000 × 0.003333 ÷ 0.550073 = 605.98
How does this calculator work?
PMT = PV·r/(1−(1+r)^−n) gives the periodic withdrawal; n = −ln(1−PV·r/PMT)/ln(1+r) gives the duration. Enter a savings balance, interest rate and one of (duration, withdrawal amount) to solve for the other. The balance never depletes when interest exceeds the withdrawal.
Formula
How this is calculated
The withdrawal calculator applies the present-value-of-annuity formula in two directions. In "withdrawal amount" mode, it solves PMT = PV·r / (1 − (1+r)^−n) for the payment that empties the account exactly after n periods. In "duration" mode, it rearranges to n = −ln(1 − PV·r / PMT) / ln(1+r) to find how many periods the balance lasts.
When the interest rate is zero both formulas simplify: PMT = PV / n and n = PV / PMT. If the interest earned per period (PV·r) equals or exceeds the withdrawal, the balance never depletes — the calculator flags this as an indefinite result rather than returning a misleading finite number.
Assumptions: withdrawals are made at the end of each period (ordinary annuity), the interest rate is constant, and the final withdrawal reduces the balance to exactly zero. Real drawdown strategies often account for inflation, sequence-of-returns risk, and variable spending — treat this result as a mathematical baseline, not financial advice.
Frequently asked questions
A common rule of thumb is 4% of the initial balance per year (the "4% rule"), derived from historical US stock and bond returns. This calculator lets you test any rate against your balance and time horizon. For longer retirements or lower expected returns, 3–3.5% may be more conservative.
If interest earned per period is at least as large as the withdrawal, the balance stays flat or grows — the savings never deplete. The calculator shows an "indefinite" result and displays the interest earned versus withdrawal so you can see the margin.
Yes — if your withdrawals rise with inflation but the nominal rate stays the same, the real purchasing power of the account declines faster. To model this, subtract the expected inflation rate from the interest rate and increase your periodic withdrawal by the same inflation amount.
TG we-Calculate Editorial Team. (2026). Savings Withdrawal Calculator — How Long Will Savings Last? [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/savings-withdrawal-calculator
TG we-Calculate Editorial Team. "Savings Withdrawal Calculator — How Long Will Savings Last?." TG we-Calculate. 2026. https://we-calculate.com/calculator/savings-withdrawal-calculator.
TG we-Calculate Editorial Team, "Savings Withdrawal Calculator — How Long Will Savings Last?," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/savings-withdrawal-calculator
@misc{wecalculate_savings_withdrawal_calculator, title = {Savings Withdrawal Calculator — How Long Will Savings Last?}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/savings-withdrawal-calculator}}, year = {2026}, note = {TG we-Calculate} }
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