FIRE Calculator

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Plan your financial independence in one place, entirely in your browser. Enter your initial capital, an expected annual return, and your yearly spending, and the FIRE calculator simulates your money year by year: each year your balance earns the return, then your expenses are withdrawn, until the money runs out. The headline figure shows exactly how many full years your savings can support your FIRE lifestyle. Because the future is uncertain, the tool also builds an 11×11 sensitivity table that varies your capital and your spending from −25% to +25% in 5% steps, so you can see at a glance how fragile or robust your plan is. When your return covers your spending the money never runs out, shown as ∞. Everything is computed locally with no sign-up and nothing sent to a server — free, fast, and private.

万
%
万/yr

Your money lasts

28yr

300万 · 20万/yr

The table below explores how many years your money lasts as capital and spending shift ±25%.

Capital \ Expense15万/yr16万/yr17万/yr18万/yr19万/yr20万/yr21万/yr22万/yr23万/yr24万/yr25万/yr
225万28yr24yr22yr20yr18yr16yr15yr14yr13yr12yr12yr
240万32yr28yr25yr22yr20yr18yr17yr16yr15yr14yr13yr
255万38yr32yr28yr25yr22yr20yr19yr17yr16yr15yr14yr
270万47yr38yr32yr28yr25yr23yr21yr19yr18yr16yr15yr
285万61yr45yr37yr32yr28yr25yr23yr21yr19yr18yr17yr
300万∞56yr43yr36yr31yr28yr25yr23yr21yr20yr18yr
315万∞85yr53yr42yr36yr31yr28yr25yr23yr21yr20yr
330万∞∞72yr50yr41yr35yr31yr28yr25yr23yr22yr
345万∞∞∞65yr48yr40yr35yr31yr28yr25yr24yr
360万∞∞∞∞60yr47yr39yr34yr31yr28yr26yr
375万∞∞∞∞88yr56yr45yr39yr34yr31yr28yr

Rows: initial capital. Columns: annual expense. The highlighted centre row, column, and cell are your original inputs. ∞ means the money never runs out.

How to use

Enter three numbers: your initial capital (in 万), your expected annual return as a percentage, and your expected annual expense (in 万). The result updates instantly. The big number at the top is how long your money lasts for your exact inputs; the table below shows the same calculation for capital and spending scenarios ±25% around your input. The highlighted centre row, column, and cell mark your original figures. Use the Copy button to grab the whole table.

Frequently asked questions

How is the number of years calculated?
Each simulated year, your balance first grows by the annual return, then your annual expense is withdrawn: year-end balance = capital × (1 + return) − expense. A year counts as fully funded when the year-end balance is at least zero. As soon as a year cannot be fully funded, the FIRE period ends and the tool reports the number of fully-funded years. If your capital cannot even cover the first year it shows 0.
What does ∞ mean in the table?
∞ means your money never runs out. This happens when the annual return is greater than or equal to your spending rate (expense ÷ capital), so the balance never shrinks. To avoid an endless loop the simulation also caps at 500 years; if your savings survive that long they are likewise shown as ∞.
Why does the table vary capital and spending?
A single estimate hides how sensitive your plan is to assumptions. By recalculating across capital and expense scenarios from −25% to +25%, the 11×11 table reveals how much earlier you could retire with a little more saved, or how a higher cost of living shortens the runway — far more useful than one fragile number. Note this is a simplified model that assumes a constant return and ignores inflation, taxes, and fees, so treat the results as estimates, not financial advice.