FIRE — Financial Independence, Retire Early — is the goal of saving aggressively enough that investment income can cover your living expenses decades before traditional retirement age. This calculator estimates your FIRE number and how many years of saving it will take to reach it.
How the FIRE number is calculated
The core of FIRE is the 25x rule, derived from the 4% safe withdrawal rate: multiply your desired annual spending by 25 to get the portfolio size that can sustain it indefinitely. If you want $40,000 a year, your FIRE number is $1 million; if you want $60,000, it is $1.5 million.
Why your savings rate matters most
The single biggest lever in FIRE is the percentage of income you save. At a 50% savings rate, you can reach financial independence in roughly 17 years regardless of income, because saving half means you only need to replace half your spending. At a 25% savings rate it takes closer to 32 years, and at 10% it stretches past 50 years.
A worked example
Suppose you spend $48,000 a year and earn $80,000 after tax, saving $32,000 annually. Your FIRE number is $1.2 million (25 x $48,000). Starting from zero at a 7% return, consistent $32,000 annual contributions reach that target in about 19 years.
Making FIRE realistic
- Focus on the big three expenses — housing, transportation, and food — where cuts have the largest impact on your savings rate.
- Build in a margin of safety; some FIRE savers target a 3.5% withdrawal rate for extra security.
- Plan for healthcare, which is a major cost gap before Medicare eligibility at 65.
- Consider Coast FIRE — saving enough early that growth alone reaches your number by traditional retirement age, letting you ease off contributions.