Fire Horizon
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When can you retire?

A real 1,000-run Monte Carlo, live in your browser: enter your age, savings, and plan, and see the earliest you can retire and the odds your money lasts — updating as you type.

Your FIRE number

$1,250,000

$50,000/yr ÷ 4%

Earliest you can retire

Age 51

≈ 2042 · in ~16 yrs

Money lasts to 95

82%

of 1,000 simulations

Save $500 more/mo → retire ≈ 1.3 yrs earlierSpend 10% less in retirement → retire ≈ 1.1 yrs earlier
$0$1M$2M$3Mage 40age 50age 60age 70FIRE · $1.3Mretire 51worst 10% runs dry ~73

1,000 simulated futures · 7% real return, 15% volatility · drawn down to age 95

Save this plan — freeRuns in your browser · nothing is stored until you sign up

Not financial advice — a projection from your own assumptions.

Beyond a one-time estimate

A calculator gives you a number. We keep it true.

The math above runs on numbers you typed. Save the plan and it runs on your real accounts instead — free.

Runs on your real money

Link a brokerage with Plaid or drop in a CSV, and this exact chart tracks your actual balances — updating as markets move and you invest. No more re-typing estimates.

Tells you if you’re on track

Your Readiness score re-runs this Monte Carlo on your real net worth and answers what matters: on track for your age, will it last, is your emergency fund covered.

Your whole net worth, in one place

Investments, cash, property and debts together — with a savings rate pulled from your real deposits and your dividend income counted. All free.

Same math here and inside — every formula is hand-checkable on the methodology page.

FIRE calculator questions

What is a FIRE number?
Your FIRE number is the portfolio size where work becomes optional: annual retirement spending ÷ your safe withdrawal rate. At the classic 4% rate that's 25× spending — $50,000 a year needs $1,250,000 invested.
What is the 4% rule?
A rule of thumb from the Trinity study: withdraw 4% of your starting portfolio in year one, adjust for inflation each year after, and a diversified portfolio has historically lasted 30+ years. The withdrawal-rate field lets you test more conservative rates like 3.5%.
What does the "money lasts" percentage mean?
It is a Monte Carlo success rate. We simulate 1,000 market futures around your expected return with 15% annual volatility, retire you the month you reach your number, then draw your spending down. The percentage is how many of those 1,000 futures still have money at your plan-to age.
Why does it ask for a "real" return?
Real means after inflation, so every figure the calculator shows is in today’s dollars — no separate inflation guess needed. A 7% real return roughly matches the long-run US stock market (about 10% nominal minus about 3% inflation).
Is this financial advice?
No — it is an educational projection computed from your own assumptions, and markets do not owe anyone their historical average. Every formula is documented on our methodology page so you can check the math yourself.

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This is one number. Fire Horizon tracks the whole plan.

Link your brokerage or drop in a CSV, and watch your real net worth, this date, and the odds your money lasts — updating with every contribution.

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