fuegoCalc: FIRE Calculator

Test your plan against every US market since 1871, entirely on your device. Real history, not Monte Carlo. Pay once, own it forever — no subscription, no account.

fuegoCalc tests your retirement plan against every historical US market window as far back as 1871 — including the Great Depression, the 1970s stagflation, the dot-com bust, and 2008. Your success rate is the percentage of those windows in which your money lasted.

Unlike Monte Carlo simulators that rely on randomized or projected returns, fuegoCalc uses the actual stock returns, bond returns, T-bill yields, and CPI inflation that occurred in each historical period. A 95% success rate means exactly that: a plan like yours made it in 95 of 100 historical start years.

The engine is validated against the published Trinity study: a 4% withdrawal rate with a 75/25 portfolio over 30 years scores 96.8% in fuegoCalc, matching the study's canonical result.

WHAT YOU CAN MODEL • Current age, retirement age, and plan length • Portfolio size and asset allocation • Annual savings before retirement • Annual spending in retirement, with Flat / Bernicke / Smile / % of portfolio models — tunable decline-start age for the spending-tapers-with-age models • Social Security with start age and inflation toggle • Pro: lump-sum events, multi-period savings brackets, additional income streams

WHAT YOU SEE • Headline historical success rate • Median portfolio path with 10–90% range • Tap any age for median, 25th, and 75th percentile values • "All Sims" view shows every historical window as a line • Sensitivity Analysis (Pro): how outcomes shift with savings, retirement age, and spending • Year-by-year percentile table with full-precision values (Pro) • Minimum portfolio at retirement needed for ≥95% historical success • Multiple saved scenarios with side-by-side comparison (Pro) • PDF and CSV export (Pro)

NINE ASSET CLASSES (Pro) US Large Cap (since 1871) • US Small Cap (1928) • 10-Year Treasury (1871) • Long-Term Treasury (1920) • Cash / T-bills (1871) • Corporate Bonds (1928) • REITs (1972) • Gold (1928) • TIPS (1871*)

*Pre-1982 TIPS use a disclosed constant-yield assumption (see Data Integrity).

DATA INTEGRITY Built on freely-available historical data with full attribution to Robert Shiller (Yale), Aswath Damodaran (NYU Stern), FTSE Nareit, FRED, and NBER macrohistory. TIPS and Long-Term Treasury returns are constructed from year-end yields with mark-to-market pricing and validated against published fund returns (correlations 0.97 and 0.99). Where a series can be honestly constructed from real macro data, we construct it and label it — TIPS before 1982 assume a constant 2% real yield applied to actual CPI, disclosed plainly in Settings. Where no honest construction exists, we cut the series instead of faking it: REITs start in 1972 and gold in 1928 because that's where the real data starts. fuegoCalc is not affiliated with or endorsed by any of these sources.

PRIVACY We collect nothing. No analytics, no telemetry, no third-party SDKs. Your scenarios live on your device (with optional iCloud sync to your private database).

ONE-TIME PURCHASE The core simulator is free — real inputs, real success rate, every historical path. Pro is a single one-time unlock: no subscription, no account, no upsell emails. We can't email you, because we don't know who you are.

DISCLAIMER — PLEASE READ fuegoCalc is provided for informational and educational purposes only. It is NOT financial, investment, tax, or legal advice and must not be relied upon as such. Outputs are historical simulations, not predictions; your actual results will differ. The model intentionally simplifies or omits taxes, fees beyond your input, longevity risk, healthcare costs, market regime changes, and many other real-world factors. Past market behavior does not guarantee future results. Always consult a qualified financial, tax, or legal professional before making any retirement, investment, or financial decisions. Decisions based on fuegoCalc's output are at your own risk. Prodigal Panda LLC accepts no liability for any losses or damages arising from use of this app.