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FIRE Calculator: Your Financial Independence Number
Financial independence means your investments can pay for your life. Enter what you spend and save to see your FI number and how many years it takes to get there.
How FIRE math works
Your FI number is your yearly spending divided by a safe withdrawal rate. At 4% that is spending × 25. Once your portfolio reaches it, withdrawals can in theory cover your costs for the rest of your life.
The calculator then grows your current investments each year at the real return (return after inflation) and adds your yearly savings until the balance passes the FI number. Using a real return keeps everything in today's dollars, so the target does not have to rise with prices.
Example: $40,000 spending, $30,000 saved a year
With $100,000 already invested, saving $30,000 a year at a 5% real return reaches the $1,000,000 FI number in 17 years. Saving $40,000 a year cuts that to 15 years; saving $20,000 stretches it to 22.
The flavours of FIRE
- Lean FIRE: a frugal budget, often under $40,000 a year, so a smaller target.
- Fat FIRE: a comfortable budget of $100,000 or more, needing $2.5 million or more.
- Coast FIRE: you have saved enough that growth alone will reach your target by a normal retirement age, so you only need to earn your living costs.
- Barista FIRE: part-time work covers some expenses, so investments only need to cover the rest.
Remember to budget for health insurance before Medicare at 65 and for taxes on withdrawals; both are easy to underestimate.
Frequently asked questions
What is a FIRE number?
It is the amount of invested money that can cover your yearly spending indefinitely. At a 4% withdrawal rate it is 25 times your annual expenses: $40,000 a year of spending needs $1 million.
Why does savings rate matter more than income?
Saving more does two things at once: it grows your investments faster and it shows you can live on less, which lowers the target. Someone saving 50% of take-home pay can reach FI in roughly 17 years from zero.
Is 4% safe for an early retirement?
The 4% rule was tested over 30-year retirements. For 40 to 50 years, many early retirees plan on 3.25% to 3.5% for extra safety, which means a target of about 29 to 31 times spending.