FIRE Calculator
Plan your path to Financial Independence & Early Retirement with the 4% rule.
The FIRE Calculator maps the math behind Financial Independence, Retire Early — the movement built on one elegant idea: once your investments can safely cover your annual spending forever, you are financially independent. The tool computes your 'FIRE number' using the classic 4% rule (target = annual spending ÷ 0.04), then projects how many years of disciplined saving it takes you to get there.
Enter your annual spending, current savings and monthly contribution, choose an expected real (after-inflation) return and a safe withdrawal rate, and the tool simulates month by month until your portfolio crosses the target. It reports the years to FIRE and, if you enter your age, the age at which you could retire — then lets you experiment: saving $200 more per month, or trimming spending, can pull the date years closer.
Like every projection, this one simplifies: returns are assumed constant rather than volatile, taxes and lifestyle changes are ignored, and the 4% rule itself is a historical guideline with a high but not guaranteed success rate. Use it as motivation and a planning compass rather than a promise. All math runs locally in your browser.
FIRE number
$1,250,000.00
50,000 spending at 4.00% withdrawal
Years to FIRE
20.67
FI at age 50.67
Current progress
8.00%
$100,000.00 saved
FIRE number = annual spending ÷ safe withdrawal rate (the classic 4% rule). Projection assumes a constant 7.00% real return after inflation. Simulations are estimates — sequence-of-returns risk, taxes and lifestyle changes all matter.
How to use the FIRE Calculator
- Enter your current age (optional, for the retirement age estimate).
- Type your annual spending — this drives the whole plan.
- Enter your current savings balance and monthly savings contribution.
- Set an expected real annual return (5–7% after inflation is a common planning range).
- Keep the safe withdrawal rate at 4% or adjust it, then read your FIRE number, years to FIRE and age at FIRE.
Frequently asked questions
What is the 4% rule?
The 4% rule says you can withdraw 4% of your portfolio in your first retirement year (adjusting for inflation after) with a high historical probability of the money lasting 30 years. Your FIRE number is therefore simply annual spending ÷ 0.04 — for $50,000 of spending, $1.25 million.
What does 'real return' mean and why use it?
A real return is your investment return minus inflation. Using real returns throughout keeps the calculation in today's dollars: your spending and FIRE number stay comparable to today's prices, and the simulation is naturally inflation-adjusted.
Is early retirement realistic for most people?
It depends far more on the savings rate than on income: the less you spend relative to what you earn, the faster you reach FIRE. Someone saving 50% of take-home pay can theoretically reach FIRE in roughly 15–17 years at average market returns; at a 10% savings rate it takes far longer. Run your real numbers here and see where you stand.
What risks does this calculator ignore?
Sequence-of-returns risk (a market crash early in retirement hurts more than later), taxes, healthcare costs before Medicare age, inflation spikes, and changing spending needs. Many FIRE planners build a margin of safety by targeting a withdrawal rate below 4% or a portfolio that outlives their needs by a decade.
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