About the Coast FIRE Calculator
Have you reached Coast FIRE? Find the amount that, left to grow untouched, funds retirement at your target age.
Also known as: coast fire number, coast retirement calculator, coastfi.
How to use this calculator
- Enter current age, retirement age, annual retirement spending, withdrawal rate and the other fields.
- 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
Coast number = FIRE number ÷ (1 + r)^(years to retirement)
Worked example
Using the values pre-filled in the calculator above:
- Current age = 30
- Retirement age = 60
- Annual retirement spending = 50,000
- Withdrawal rate = 4 %
- Real return = 5 %
- Current investments = 120,000
the calculator returns:
- Coast FIRE number today: 289,221.81
- FIRE number at retirement: 1,250,000
- Status: 41.5% of the way