FIRE Calculator – Financial Independence
The FIRE (Financial Independence, Retire Early) calculator offers two modes. Path to FIRE calculates how many years it takes to reach financial independence — including milestones, cash flow visualisation, and a withdrawal projection. Portfolio Withdrawal shows how much you can withdraw monthly and how long your portfolio will last.
What Is FIRE?
FIRE (Financial Independence, Retire Early) is a financial strategy aimed at achieving financial independence — a state where investment returns cover all living expenses. It does not necessarily mean stopping work — many people who reach FIRE continue doing work they enjoy.
Two Calculator Modes
Path to FIRE calculates how many years and at what age you can achieve financial independence. It shows a complete projection — the accumulation phase (building the portfolio) and the withdrawal phase (after reaching FIRE until the chosen end age). It includes milestones, cash flow visualisation, and Lean/Fat/Coast FIRE variants.
Portfolio Withdrawal is for those who already have savings or are planning withdrawals. Enter your portfolio, monthly withdrawal, and pension — the calculator shows how long the portfolio will last and how it will evolve.
The FIRE Number and the 4 % Rule
The FIRE number is the target portfolio value: Annual expenses / SWR. With expenses of $3,500 per month ($42,000 per year) and an SWR of 4 %, the FIRE number is $1,050,000. The 4 % rule comes from the Trinity Study — a portfolio of stocks and bonds historically lasted at least 30 years at a 4 % annual withdrawal rate.
FIRE Variants
Lean FIRE (70 % of expenses) — a minimalist lifestyle. Faster to achieve, less comfort. Fat FIRE (130 % of expenses) — a more comfortable version with room for travel and hobbies. Coast FIRE — the amount at which you can stop saving and let investments grow until retirement.
Savings Rate — The Key Variable
The savings rate is the most important factor. At 10 % the path to FIRE takes roughly 50 years. At 50 % about 17 years. At 70 % around 8 years. Increasing the savings rate has a dual effect — more money into investments and lower expenses (a smaller FIRE number).
The Withdrawal Phase
After reaching FIRE you stop saving and begin withdrawing from the portfolio. The portfolio continues to grow through returns but also declines due to withdrawals. The chart shows both phases — blue columns (accumulation) and green columns (withdrawal). From the state pension age onward the required portfolio withdrawal decreases.
What the Calculator Does Not Account For
The model assumes a constant return and expenses rising only with inflation. It does not account for taxes on returns, one-off expenses, changes in life circumstances, or market volatility. Sequence of returns risk can significantly affect withdrawal success — bad years at the start of withdrawal are more dangerous than bad years in the middle.
