FIRE Calculator
Calculate your FIRE number and see how many years until work becomes optional — enter your expenses, savings, and monthly investment.
Your savings rate matters more than your salary — saving 50% of income reaches FIRE in ~17 years at any income level.
25×
Your FIRE number — 25 times your annual expenses, based on the 4% rule
50%
Savings rate that gets you to FIRE in roughly 17 years, regardless of income
17yr
Years to FIRE at a 50% savings rate — down from 40+ years at a 10% rate
The math behind financial independence
Why FIRE is a savings rate game, not an income game.
Savings rate beats income
A high earner saving 5% and a modest earner saving 50% will reach FIRE at roughly the same time — because the FIRE number scales with spending. Cutting expenses is the fastest accelerator, both by reducing the target and increasing the savings rate.
The 4% rule explained
Based on historical data, a 4% annual withdrawal from a diversified portfolio has succeeded 95%+ of the time over 30-year periods. Multiply your annual expenses by 25 and you have the portfolio size needed to sustain them indefinitely.
Lean FIRE vs Fat FIRE
Lean FIRE means retiring on minimal expenses ($25–40k/year). Fat FIRE means retiring with a lifestyle no different from high-earning years ($80–150k+). Your target is personal — this calculator works for any spending level.
How the FIRE Calculator Works
Formula
FIRE Number = Monthly Expenses × 12 × 25
(4% rule: withdraw 4%/year indefinitely)
Years to FIRE = compound monthly until balance ≥ FIRE Number
Balance(m+1) = Balance(m) × (1 + r/12) + Monthly SavingsEnter your monthly expenses
Your current total monthly spending — this determines your FIRE number.
Enter current savings
Total invested assets today (not home equity or cash).
Set monthly investment
How much you add to investments each month.
Choose expected return
7% is a conservative inflation-adjusted S&P 500 estimate.
Read your FIRE number and timeline
Your target portfolio size and years until you hit it.
The FIRE number is 25× annual expenses — the portfolio size at which a 4% withdrawal covers your costs indefinitely based on historical market data.
Years to FIRE is calculated by simulating monthly portfolio growth (contributions + compounding) until the balance reaches your FIRE number.
Frequently Asked Questions
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