Coast FIRE Age Calculator
Find out at what age you can stop actively saving and let compound interest do the rest.
How much you invest each month until you reach Coast FIRE.
Use a real return. 7% is the common inflation-adjusted default.
What is Coast FIRE Age?
Coast FIRE Age is the age at which your invested assets are large enough that even without any additional contributions they will grow to your full FIRE number by your target retirement age.
Once you reach your Coast FIRE age, you only need to cover your living expenses. You no longer need to save for retirement.
How is it calculated?
Your Coast FIRE number is what you would need invested today for compound growth alone to carry you to your FIRE number:
That number rises every year, because each year leaves less time to compound. The calculator projects your balance forward month by month with your contributions, and reports the first age at which your balance overtakes that rising line.
FAQ
Why does the Coast FIRE number go up over time?
Because compound growth needs time. At 35 with retirement at 65 you have 30 years of growth ahead. At 45 you only have 20, so you need a bigger starting balance to end up at the same place.
What return rate should I use?
Use a real return, meaning after inflation. 7% is the common default. Conservative planners use 5 to 6%. Do not enter a nominal return like 10%, or the result will overstate what you actually have in today's money.
What if it says not reachable?
Your contributions are growing your balance more slowly than the Coast FIRE line is rising. You can still reach your FIRE number by retirement, but you would have to keep contributing the whole way rather than coasting.
Does Coast FIRE mean I can stop working?
No. It means you can stop saving for retirement, but you still need income for daily expenses. Many people switch to lower-stress jobs at this point.