Fire Calculator
Free Fire Calculator for investing. Enter your numbers to see returns, costs, and optimized scenarios instantly. Enter your values for instant results.
Formula
FIRE Number = Annual Expenses / Safe Withdrawal Rate
Your FIRE number is the portfolio size needed to sustain your lifestyle indefinitely. At a 4% withdrawal rate, you need 25x your annual expenses. The calculator then projects how long it takes to reach that number given your current savings, annual savings rate, and expected investment returns.
Worked Examples
Example 1: Standard FIRE — $50k Expenses
Problem: $50,000 annual expenses, $100,000 saved, saving $30,000/year, 7% returns, 4% withdrawal rate.
Solution: FIRE Number: $50,000 / 0.04 = $1,250,000\nProgress: $100,000 / $1,250,000 = 8%\nSavings rate: $30,000 / $80,000 = 37.5%\nYears to FIRE: ~18 years (with compound growth)
Result: FIRE Number: $1,250,000 | ~18 years to FIRE | Savings rate: 37.5%
Frequently Asked Questions
What is FIRE (Financial Independence, Retire Early)?
FIRE is a movement focused on extreme savings and investment to achieve financial independence much earlier than traditional retirement age. The core idea: save 50-70%+ of your income, invest aggressively, and retire when your investment portfolio can sustain your living expenses indefinitely. FIRE number = Annual Expenses / Safe Withdrawal Rate (typically 4%). With $50,000 annual expenses and 4% withdrawal rate, your FIRE number is $1,250,000.
What are Lean FIRE, Fat FIRE, and Coast FIRE?
Lean FIRE: Retire with minimal expenses ($20-40k/year), often involving frugal living, geographic arbitrage, or van life. Fat FIRE: Retire with comfortable or luxury expenses ($100k+/year), requiring a much larger portfolio. Coast FIRE: Have enough invested that compound growth alone will reach your FIRE number by traditional retirement age — you still work but only to cover current expenses, not to save more. Barista FIRE: Semi-retired with part-time work for healthcare and spending money.
How accurate are the results from Fire Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.
What formula does Fire Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.
Does Fire Calculator work offline?
Once the page is loaded, the calculation logic runs entirely in your browser. If you have already opened the page, most calculators will continue to work even if your internet connection is lost, since no server requests are needed for computation.