Understanding your result
The corpus is the amount needed on the retirement date to fund the modeled withdrawals. It deliberately reaches approximately zero after the final withdrawal. It includes no inheritance reserve, emergency buffer, or allowance for living beyond the entered period.
To estimate contributions toward this retirement-date fund target, use the Savings Goal Calculator with the years remaining and assets already allocated to retirement.
The formula
Each full year’s spending is withdrawn at the beginning of that year. The remaining balance earns the annual return before the next withdrawal. Rates are decimals. Summing the discounted withdrawals also handles equal inflation and return rates without division by zero.
A retirement with no growth or inflation
At retirement, monthly expenses of 1,000 equal annual spending of 12,000. Funding twenty years with no inflation and no investment return requires 240,000. A separate reserve would need to be added to that figure.
How to use this calculator
- Enter recurring retirement expenses at today’s prices.
- Set the wait until retirement and the number of retirement years to fund.
- Test different inflation and post-retirement returns, then inspect the annual withdrawal schedule.
A finite target is sensitive to its assumptions
Adding retirement years increases the amount that must be funded. Expenses that do not recur every year, such as major home repairs, may need a separate provision. If pension income covers part of your spending, enter the remaining expense gap only when its future purchasing power is modeled consistently.
Constant growth hides sequence risk: poor returns early in retirement can have a greater effect when you are withdrawing money. This deterministic schedule cannot estimate the probability of running out of funds. It is useful for checking the arithmetic of an explicit scenario, not selecting a safe withdrawal rate.
Assumptions & limitations
What this calculation assumes
- Expenses rise once each retirement year at a constant rate.
- Withdrawals occur at the beginning of each year.
- No assets are reserved beyond the modeled retirement period.
What to keep in mind
- No longevity probabilities, tax, fees, or market volatility are modeled.
- This target is not a personalized retirement recommendation.
Common questions
Does the result include my current investments?
No. It estimates the required future fund. Use a savings-goal calculation with your current balance to estimate contributions toward that target.
Why does the last balance approach zero?
The formula funds exactly the entered withdrawals. A remaining legacy amount or safety reserve requires additional capital.