About the Retirement Duration Calculator
How many years your retirement savings will last with fixed monthly spending and a steady return.
Also known as: how long will retirement savings last, money duration, retirement longevity.
How to use this calculator
- Enter savings, monthly spending, annual return.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
n = −ln(1 − B·r/P) / ln(1 + r)
Worked example
Using the values pre-filled in the calculator above:
- Savings = 500,000
- Monthly spending = 3,000
- Annual return = 4 %
the calculator returns:
- Savings last: 20 yr 3 mo
- Years: 20.31