Retirement Withdrawal Calculator
Work out the fixed monthly amount you can withdraw from a retirement balance so it is exactly exhausted at the end of your retirement (beginning-of-period withdrawals).
Input Data
Results
At a glance:The Retirement Withdrawal Calculator assumes a balance at retirement and a fixed monthly drawdown that exactly exhausts the fund at the end of the horizon, using a beginning-of-period (annuity due) model: first find the end-of-period payout a_ord = PV ÷ [(1 − (1+i)^−n) ÷ i], then convert to beginning-of-period a_due = a_ord ÷ (1+i), where i is the monthly rate and n is total months. The total withdrawn is far above the principal because the unwithdrawn balance keeps earning.
Formula
Monthly rate i = annual return ÷ 12; total months n = retirement years × 12.
End-of-period payout a_ord = PV ÷ [(1 − (1+i)^−n) ÷ i].
Beginning-of-period payout a_due = a_ord ÷ (1+i).
Total withdrawn = monthly withdrawal × n; total interest = total withdrawn − balance.
$$a_{\text{ord}} = \dfrac{PV}{\left(1 - (1+i)^{-n}\right) / i}$$$$a_{\text{due}} = \dfrac{a_{\text{ord}}}{1+i}, \quad i = \dfrac{r}{12}, \; n = 12 \times \text{Years}$$How to Use
- Enter the fund balance at the start of retirement.
- Enter the retirement horizon and the annual return during retirement.
- View the monthly withdrawal, total withdrawn and total interest earned.
FAQ
How is this related to the 4% rule?
The 4% rule is a rule of thumb: withdraw 4% of the balance in the first year and adjust for inflation after. This tool uses the precise annuity formula to find the fixed monthly amount that exactly exhausts the balance over a chosen horizon, without inflation adjustment. If the annual amount it gives is far above 4% of the balance, your withdrawal is aggressive and the depletion risk is higher.
Why use beginning-of-period withdrawals?
Retirees usually draw living expenses at the start of each month, so a beginning-of-period (annuity due) model fits reality. Because each draw happens one step earlier, the same balance and horizon yield a slightly lower monthly amount than an end-of-period withdrawal.
Does it account for inflation and tax?
No. It assumes a fixed return and a constant withdrawal, ignoring inflation and tax. Real retirement spending rises with inflation and purchasing power falls materially over long horizons; use a conservative return and build in a buffer for medical and other costs.
How does this differ from the Systematic Withdrawal Plan (SWP) calculator?
Both handle drawing cash from a balance, but they answer opposite questions. This calculator works backwards: given balance, horizon and return, it finds the safe monthly draw that exhausts the fund exactly at the end. The SWP calculator works forwards: given principal, return and a fixed monthly draw, it simulates the remaining balance after N years. If your start point is 'I want it to last X years', use this one; if it is 'I want to spend Y a month, will it last?', use the SWP calculator. They can be used together to cross-check.
Why beginning-of-period, and how much does it differ from end-of-period?
This calculator uses an annuity-due (beginning-of-period) model, which mirrors retirees taking living expenses at the start of the month. The key difference is the interest timing: under end-of-period, the month's money earns one more month of interest before being drawn; under beginning-of-period, it is drawn at the start and earns one month less. So the same balance, horizon and return give a slightly lower beginning-of-period amount. The formula is a_due = a_ord ÷ (1 + monthly rate). The gap depends on the rate — larger when rates are high, negligible when low — usually a fraction of a percent to a few percent, but the beginning-of-period model better reflects real cash-flow timing.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.