This FIRE calculator finds your financial independence number (25× annual spending at the classic 4% rule) and simulates how many years of saving and compounding stand between you and it.

FI Number–
Years to FI–
Progress Today–

The savings rate is the master variable: cutting spending attacks the problem from both sides (less to save toward and more saved per year) — which is why the FI community obsesses over it rather than returns. The 4% rule comes from the Trinity study’s 30-year US windows; longer retirements argue for 3.25–3.5% (adjust the SWR field and watch the target — and timeline — grow). Constant-return simulation smooths a jagged real path: treat the year as a planning center, not a promise.

FI Number = Spending ÷ SWR — Then Compounding Does the Walking

At a 4% withdrawal rate the target is the famous 25× spending; the timeline is a boring, beautiful simulation: balance grows by return, plus your annual savings, until it crosses the target. Coast FI, Barista FI and other waypoints are the same line read at different altitudes (Coast = the point where compounding alone finishes the trip by traditional retirement age). Foundation first: our Emergency Fund Calculator before any of this matters. Part of our Finance Calculators collection.

Worked Example (Verified by Simulation)

  • $100k saved, $40k/yr added, $50k spending target, 7%, 4% SWR (defaults): FI number $1.25M → reached in 15 years (balance crosses at ≈ $1.28M) — the compounding tail does more work than the last five years of contributions combined
  • The double lever: cut target spending to $40k and the number drops to $1.0M and (if the $10k saved joins contributions) the timeline compresses to 12 years — spending cuts are squared, return boosts are linear and speculative
  • Conservative variant: SWR 3.5% raises the target to $1.43M and adds ~2 years here — cheap insurance priced explicitly
  • Coast check: stop contributing at year 8 (~$582k) and 7% growth alone still crosses $1.25M by about year 20 — optionality arriving long before the finish line

Honest Caveats

  • Sequence risk: returns arriving in a bad order near the target date matter more than the average — the flat-rate line here is a map, not terrain.
  • Taxes, healthcare (pre-Medicare in the US), and spending drift are real budget lines the single “spending” input must honestly include.
  • The 4% rule is a historical US result, not a physical law; valuations, longevity and geography argue their cases in the SWR field.
  • FI is a continuum of freedom ( FU-money, Coast, Barista, Lean, Fat) — the percentage-funded card may be the most useful number on the page.

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Frequently Asked Questions

What is my FIRE number?

Annual spending divided by your safe withdrawal rate — at 4%, that’s 25× spending: $50,000/year needs $1,250,000 invested. Leaner spending or a lower withdrawal rate move the number in opposite directions ($40k at 4% = $1.0M; $50k at 3.5% = $1.43M). This calculator simulates the years to reach it from your savings and contributions.

How long will FIRE take me?

Simulate: each year, balance × (1 + return) + annual savings, until the FI number is crossed. The defaults ($100k start, $40k/yr, 7%) take 15 years to $1.25M. Savings rate dominates the answer — doubling contributions cuts far more time than plausible return increases.

Is the 4% rule safe?

It survived every 30-year US window in the Trinity study’s data (including 1929 and 1966 starts) for a balanced portfolio with annual adjustments — strong evidence, historical scope. Early retirees facing 50+ year horizons commonly plan 3.25–3.75%; this calculator exposes the SWR so you can price your own caution.

What return should I assume?

Long-run diversified equities have returned ~7% real (US history) — but nominal vs real must match your spending input (use nominal returns with future, inflation-grown spending; or real returns with today’s-dollar spending, the convention here). Conservative planners model 5–6% nominal for balanced portfolios. Our Real Rate of Return Calculator converts between the dialects.

What’s Coast FIRE?

The point where your existing balance, left to compound untouched, reaches your FI number by traditional retirement age — after which you only need to cover current expenses (“coasting”). In the defaults’ path, ~$582k at year 8 coasts across $1.25M by about year 20 unassisted: calculate your coast point by setting annual savings to 0 and raising years.

Is this FIRE calculator free?

Yes — free, instant, no sign-up. A planning model, not financial advice.