Calculators / FIRE number
FIRE number calculator
Your FIRE number is the pot that pays for the rest of your life without a salary behind it. It comes from what you spend, not what you earn, which is why two people on the same income can be twenty years apart.
Today's dollars, everything included: housing, food, insurance, the car fund, holidays.
The share of the pot you take in year one, then raise with inflation.
A pension, rental profit, or Social Security if you want it counted. Reduces what the portfolio has to carry.
The same spending, five ways
FIRE is not one target. These are the same withdrawal-rate maths applied to five different lives, using the spending you set above as the middle one.
Where the 4% figure comes from, and what it assumes
The 4% rule traces back to research on historical US portfolios that asked a narrow question: what starting withdrawal, raised each year with inflation, would have survived a 30-year retirement in the worst historical run? The answer landed near 4%.
Two assumptions inside that matter for early retirement. It was built for a 30-year horizon, and someone retiring at 45 needs closer to 50. And it was drawn from a specific market history that nobody is obliged to repeat. That is the whole argument behind people using 3.25% or 3.5% instead, and the reason the slider above goes both ways.
Lowering the rate raises the target sharply. Going from 4% to 3.5% is not a 0.5% change; it is a 14% larger portfolio. Move the slider and watch the number rather than taking anyone's word for which rate is correct.
Why savings rate beats salary
The years-to-FIRE figure above depends almost entirely on the gap between what you earn and what you spend, because spending sets the target and the surplus fills it. A raise you spend moves nothing. A raise you bank moves the date twice: it fills the pot faster and it keeps the pot small.
The number is the easy half
The hard half is which account you empty first, what happens to the plan when one of you keeps working, and what health insurance costs before 65. NestEgg does that part, and remembers your answers.