Your FIRE number and retire-early age.

FIRE stands for Financial Independence, Retire Early. The goal is to accumulate a portfolio large enough that safe investment withdrawals cover all living expenses — indefinitely. Two inputs drive everything: your savings rate and your expected return.

1. 1. The FIRE number (4% rule). The most widely used target comes from the 1998 Trinity Study: withdraw 4% of your initial portfolio each year, adjusted for inflation, and your money has historically lasted 30+ years with high probability. The formula is simple — FIRE number = annual retirement spending × 25. If you need $60,000 per year, you need $1.5 million.
2. 2. Compound growth. Each year, your portfolio earns returns on both the principal and accumulated gains. At 7% nominal growth, money doubles roughly every 10 years (Rule of 72: 72 ÷ 7 ≈ 10.3). Early contributions therefore carry far more weight than contributions made later — starting at 25 instead of 35 can shave a decade off your timeline.
3. 3. Inflation adjustment.Nominal returns overstate real purchasing power. This calculator deducts CPI (default 2.5%) to show real balances in today's dollars. FIRE is achieved when the real portfolio reaches your FIRE number — not the nominal one.
4. 4. Savings rate is the most powerful lever. Increasing your savings rate does two things at once: it grows the portfolio faster, and it reduces your required retirement spend (so the FIRE number shrinks). Going from a 20% to a 50% savings rate can cut years-to-FIRE by more than half.
5. 5. Australian context. Australian investors can turbocharge FIRE with superannuation (taxed at only 15% on earnings), but super is locked away until age 60. Many FIRE seekers build both a super balance and a separate taxable investment portfolio to bridge the gap between early retirement and preservation age.