Fire Calculator
Free Fire Calculator for investing. Enter your numbers to see returns, costs, and optimized scenarios instantly. Enter your values for instant results.
Reviewed by Sahil, Senior Finance & Tax Editor
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.
What is the FIRE number and how is it calculated?
Your FIRE number is the portfolio size needed to sustain your annual spending indefinitely using a chosen safe withdrawal rate. At the commonly used 4% withdrawal rate, the FIRE number is 25 times your annual expenses (1 ÷ 0.04 = 25). Someone planning to spend $50,000/year would target a $1.25 million portfolio. A more conservative 3.5% withdrawal rate — often preferred for very long, multi-decade early retirements — raises the multiple to about 28.6 times expenses instead.
What's the difference between Lean FIRE, Fat FIRE, and Barista FIRE?
Lean FIRE targets a minimal, tightly budgeted annual spending level (often under $40,000/year), requiring the smallest portfolio but the least spending flexibility. Fat FIRE targets a more generous lifestyle budget, requiring a much larger portfolio in exchange for more comfort and less restriction. Barista FIRE sits in between — retiring from a full-time career while continued part-time or lower-stress work covers a portion of expenses, reducing the portfolio required compared to full FIRE at any spending level.
References
Reviewed by Sahil, Senior Finance & Tax Editor · Editorial policy