FIRE Calculator

Your savings rate sets the date, not your salary

The counter-intuitive result at the centre of this idea is that the years to independence depend almost entirely on the percentage of take-home pay you save, and barely at all on the amount. Someone saving 10 percent is looking at four decades. At 25 percent it is roughly thirty-two years, at 50 percent about seventeen, and at 65 percent closer to ten. The reason is that saving more does two things at once: it fills the pot faster and it shrinks the pot you need, because the target is a multiple of what you spend.

This is also why a raise spent entirely does not move the date at all, and a raise saved entirely moves it a great deal. Lifestyle inflation is not a moral failing here; it is simply the single most effective way to postpone financial independence indefinitely.

What the four percent rule actually says

It comes from studies of American portfolios over thirty-year retirements, and it says that withdrawing four percent of the starting balance, adjusted for inflation each year, survived almost every historical thirty-year window. It was never a law, and it carries assumptions worth knowing: a thirty-year horizon, a stock-heavy portfolio, and US market history, which is among the best in the world and may not repeat.

For a retirement lasting forty or fifty years, most people planning seriously use something between three and three and a half percent, which raises the target considerably — at three percent your number is 33 times spending rather than 25. The withdrawal field above is there so you can see what that costs in years.

Coast FIRE, the milestone most people reach first

There is a point where the money already invested will grow to a full retirement by 65 without another cent added. That is a meaningfully different freedom from full independence: you still work, but only enough to cover today, and you can choose worse-paid work you prefer. It usually arrives a decade or more before the headline number and it is worth knowing the date.

Where the arithmetic is optimistic

A smooth average return hides sequence risk: a bad decade at the start of retirement does far more damage than the same decade later, and the averages here cannot show it. Health insurance before Medicare eligibility is a large and volatile American expense that early retirees consistently underestimate. Retirement accounts have withdrawal rules that need planning around if the money is wanted before 59½. And spending in practice is not flat — it tends to be high early, lower in the middle, and high again at the end.

Spending is the lever you control

Of the inputs above, the return is a guess and the salary is largely someone else’s decision. Annual spending is the one you can actually change, and it moves the answer twice. Cutting $500 a month adds $6,000 a year to savings and removes $150,000 from a 25× target at the same time. Nothing else in the model comes close.