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FIRE & Retirement calculator

FIRE Number Calculator

Calculate your financial independence number from annual spending and a safe withdrawal rate, plus your years to FI.

Your target yearly expenses
4% rule = 25x spend
After inflation

Finding your FIRE number and time to financial independence

Your FIRE number is the size of portfolio that can fund your retirement indefinitely. It comes from the safe withdrawal rate framing popularized by the Trinity study and William Bengen’s earlier work: historically, a retiree who withdrew 4% of their starting portfolio in year one and adjusted that amount for inflation thereafter had a high probability of not running out of money over a 30-year retirement. The 4% rule and "25× annual spending" are the same idea expressed two ways — 1 ÷ 0.04 = 25.

So the calculation is simple: FIRE number = annual spending ÷ withdrawal rate, or equivalently annual spending × 25 at a 4% rate. Spend $40,000 a year and your number is $1,000,000; a more conservative 3.5% rate raises it to about $1,143,000. Use a spending figure that includes taxes. This calculator also estimates your years to financial independence from your current savings, contributions, and expected return. Your savings rate is the dominant lever — the more of your income you invest, the faster the gap between your portfolio and your number closes.

Two cautions keep the result honest. First, enter returns as real (inflation-adjusted) figures — roughly nominal return minus inflation — so the projection is in today’s dollars and your future spending estimate stays meaningful. Second, the 4% rule is a historical heuristic, not a guarantee: it is based on past U.S. market data, assumes a stock-and-bond portfolio, and may be optimistic for retirements much longer than 30 years, which is why many early retirees plan around 3 to 3.5%. Treat the output as a planning estimate, not a promise.

Frequently asked questions

What is the 4% rule?
The 4% rule is a retirement guideline drawn from the Trinity study (and William Bengen's earlier research): historically, a retiree who withdrew 4% of their starting portfolio in the first year, then adjusted that amount for inflation each year, had a high probability of not running out of money over a 30-year retirement. Stated the other way, it implies a nest egg of 25 times your annual spending. It is a planning heuristic, not a guarantee — it is based on historical U.S. data, assumes a stock/bond portfolio, and does not account for every fee, tax, or unusually long retirement. Some early retirees use a more conservative 3–3.5% rate.
How do I calculate my FIRE number?
Divide your expected annual retirement spending by your chosen safe withdrawal rate. At a 4% rate that is annual spending ÷ 0.04, or equivalently annual spending × 25. For example, $40,000 of yearly spending implies a $1,000,000 FIRE number; a more cautious 3.5% rate raises it to about $1,143,000. Use spending figures that include taxes. For projecting how long it takes to get there, enter returns as real (inflation-adjusted) percentages so the result is expressed in today's dollars. This calculator computes both your number and your estimated years to financial independence.

Coast FIRE

Find out if your current savings will coast to a full retirement with no further contributions — and your exact Coast FIRE number.

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