FIRE calculator — financial independence

What is FIRE?

FIRE (Financial Independence, Retire Early) is a financial strategy aimed at financial independence — the point at which the returns from invested capital cover all living costs. It does not necessarily mean stopping work. Many people who reach FIRE keep working, but with the freedom to choose what they do.

The two modes of the calculator

Path to FIRE estimates how many years — and at what age — financial independence becomes possible. It shows a full projection covering the accumulation phase (building the portfolio) and the withdrawal phase (from FIRE through the chosen end-age). It includes milestones, the cash-flow donut and the Lean/Fat/Coast FIRE variants.

Portfolio withdrawal is for those who already have savings or are planning to draw down. Enter the portfolio, the monthly withdrawal and the state pension — the calculator shows how long the portfolio is expected to last and how its value evolves over time.

The FIRE number and the 4 % rule

The FIRE number is the portfolio target: annual expenses divided by the SWR. With monthly expenses of €1,300 (about €15,600 a year) and a 4 % SWR, the FIRE number is roughly €390,000. 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 reach, lower comfort. Fat FIRE (130 % of expenses) — a comfier path with room for travel and hobbies. Coast FIRE — the threshold from which you can stop adding new contributions and just let the existing portfolio compound to retirement.

Savings rate — the key variable

The savings rate is the single biggest driver of time-to-FIRE. At 10 % it takes roughly 50 years. At 50 % about 17 years. At 70 % around 8 years. Raising the savings rate has a double effect — more capital goes to investments and expenses fall, so the FIRE number itself shrinks.

The withdrawal phase

Once FIRE is reached the saving stops and withdrawals begin. The portfolio keeps growing from returns but also shrinks from withdrawals. The chart shows both phases — accumulation in blue (portfolio building) and the withdrawal years that follow. From the moment the state pension kicks in, the required portfolio draw is reduced.

What the calculator does not model

The model assumes a constant return and expenses that only grow with inflation. It does not include taxes on returns, lump-sum expenses, life changes, or market volatility. Sequence-of-returns risk can significantly affect withdrawal success — poor years early in the withdrawal phase are more dangerous than poor years in the middle.