FIRE Calculator
FIRE — Financial Independence, Retire Early — is the point where your investments can cover your living costs indefinitely without a paycheck. Your "FIRE number" is the size of portfolio that makes this possible. This calculator finds that number from your expenses and a safe withdrawal rate, then projects how many years of saving it takes to reach it, in any currency.
- FIRE number
- $1,000,000.00
- Current progress
- 10.00%
- Years to FIRE
- 18
At 4% safe withdrawal you need 1000000 invested — that is 25× your annual spending. Saving 20000 a year at 7% growth, you reach it in about 18 years.
How it works
The FIRE number flows directly from your spending and how much of a portfolio you can safely withdraw each year. Divide annual expenses by the withdrawal rate and you get the invested sum that throws off enough to live on. At the widely cited 4% safe withdrawal rate, that simplifies to 25 times your annual expenses — the famous "25× rule." A lower rate demands a bigger portfolio but adds a safety margin; a higher rate needs less but raises the risk of running dry.
The 4% figure comes from research into how a diversified portfolio survives decades of withdrawals through good and bad markets. Withdrawing 4% of the starting balance, then adjusting for inflation, historically left most portfolios intact across long retirements. It is a guideline, not a guarantee — sequence-of-returns risk, longer time horizons, and market conditions can all argue for a more conservative 3% to 3.5%.
To estimate the timeline, the calculator grows your current balance year by year: each year it compounds at your expected return and adds your annual savings, repeating until the balance reaches your FIRE number. This makes the two biggest levers obvious. Your savings rate dominates the early years, while compound growth takes over later. Cutting expenses is doubly powerful — it lowers the FIRE number and frees up more to invest at the same time. The projection assumes steady returns and constant saving, so treat it as a planning target you revisit as life and markets change.
FIRE number = annual expenses ÷ (safe withdrawal rate as a decimal) — equivalently 25 × expenses at a 4% rate. Years to FIRE is found by growing the balance each year: balanceₙ = balanceₙ₋₁ × (1 + return) + annual savings, until it reaches the FIRE number.
Worked example
With 40,000 in annual expenses and a 4% safe withdrawal rate, your FIRE number is 40,000 ÷ 0.04 = 1,000,000 — exactly 25× your spending. Starting from 100,000 (10% of the way there) and saving 20,000 a year at a 7% return, the balance compounds and tops the million mark in about 18 years.
Things to watch out for
The 4% rule is a historical guideline, not a law — early retirees facing a 40- or 50-year horizon often use 3% to 3.5% for extra safety. A weak run of returns in the first few years of retirement (sequence risk) can hurt far more than the same returns later, which fixed withdrawal rates ignore. The years-to-FIRE projection assumes constant returns and savings; real markets are volatile, so rerun it as your numbers change. If your inputs never reach the target within 100 years, the calculator flags that you are not yet on track.
Frequently asked questions
What is the 4% rule?+
It is a guideline suggesting you can withdraw 4% of your portfolio in the first year of retirement, then adjust for inflation, with a low chance of running out over about 30 years. It implies a FIRE number of 25× your annual expenses.
How is the FIRE number calculated?+
Divide your annual expenses by your safe withdrawal rate. At 4% that means 25 times your yearly spending; at 3% it rises to about 33 times, because a lower rate needs a larger portfolio to fund the same lifestyle.
What's the fastest way to reach FIRE sooner?+
Cutting expenses is the most powerful lever — it shrinks your FIRE number and frees up more to invest at the same time. Raising your savings rate and your investment return both help, but lower spending works on both sides of the equation.
Is a 4% withdrawal rate always safe?+
Not necessarily. It was modelled on roughly 30-year retirements; early retirees planning for 40 to 50 years often choose 3% to 3.5%. Market conditions and the order of returns early in retirement also affect how safe it really is.
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Disclaimer: This calculator is for educational and informational purposes only and provides estimates, not financial advice. Interest rates, taxes, fees, and local rules vary and change over time. Confirm figures with a qualified professional before making any financial decision.
Last reviewed: 2026-06-22