About FIRE Engine
FIRE Engine is a free calculator built to make one of the most important numbers in personal finance easy to see: the age you could reach financial independence and retire early.
What we do
We turn a handful of inputs — your net worth, income, expenses, expected return, and withdrawal rate — into a clear projection: your FIRE number, your savings rate, and a year-by-year chart of your net worth compounding toward the finish line. No spreadsheets, no sign-up, no jargon. Alongside the main calculator we cover the major variants of the movement — Lean FIRE, Fat FIRE, Coast FIRE, and Barista FIRE — each with its own tailored calculator.
Why it's private
The calculator runs entirely in your browser. The financial details you enter never leave your device and are never sent to a server. We believe a tool that handles sensitive money questions should respect your privacy by default. See our Privacy Policy for the full details.
A note on accuracy
Our projections are intentionally simple and transparent so you can understand every assumption. They do not replace personalized advice from a qualified financial professional, and real-world results are affected by taxes, inflation, fees, and market timing. Use FIRE Engine as a starting point for planning and conversation, not as a guarantee. Full details are in our Terms of Use.
Who we are
FIRE Engine is an independent project run by a small editorial team that follows the FIRE movement personally — people who have run these numbers on their own money for years. We built the tool we wanted ourselves: fast, private, and free of the sign-up walls and data harvesting common to financial sites. The site is supported by advertising so it can stay free to use.
Every calculation on the site is transparent by design: we publish the exact formula behind each tool so you can check our work, and the JavaScript runs in the open in your browser. We are not a bank, broker, or advisory firm, and we don't sell financial products — which means we have no incentive to nudge you toward any particular decision.
Our editorial standards
Because this is personal-finance content that people may act on, we hold every article and calculator to a consistent standard:
- Show the math. Each calculator states its formula in plain text, so you can verify the result rather than trust a black box.
- Cite primary sources. Where an article references research like the Trinity Study or rules like contribution limits, we link to the original source or the relevant government page.
- Reviewed and updated. Articles are reviewed by our editorial team before publishing and revised when the underlying facts, figures, or limits change. Each post shows its last-updated date.
- Educational, not advice. We explain concepts and do the arithmetic; we never give personalized investment, tax, or legal advice. See our Terms of Use.
Spotted an error or have a correction? We take accuracy seriously — email us at rocketwebtools1@gmail.com or use our Contact page, and we'll fix it.