Can I actually retire early?
Plug in your numbers, run 5,000 Monte Carlo simulations, get back a probability — not a single optimistic estimate.
How the simulation works
The calculator runs 5,000 Monte Carlo paths. Each year of each path samples a return from a normal distribution (default mean 7%, standard deviation 15% — close to the post-1928 S&P 500) and an inflation rate (default 2.5% mean, 1% std dev). Withdrawal in retirement uses the safe withdrawal rate you set; the classic 4% rule comes from Bengen (1994) and the Trinity Study.
We report two numbers. Success rate is whether you hit the FIRE target by your chosen retirement age. Survival rate is whether the portfolio lasts to your life expectancy. The second one traps a lot of people. Hitting the target is one thing; sequence-of-returns risk in the first 5–10 retirement years is what actually wrecks portfolios.
All math runs in your browser. We don't store your inputs. Source code on github.
Scenarios we've already crunched
If your numbers look like one of these, the article skips a few steps for you:
- Retire at 40 on $80K income, $40K expenses — 50% savings rate from age 25, the textbook FIRE path. The honest survival rate is 68%, not the 90%+ most blogs quote.
- The 25× expenses rule, stress-tested — what happens when you actually retire on the bare minimum the rule says is enough.
- Traditional vs lean vs barista FIRE — three paths, three survival rates. One of them is more reliable than the FIRE community usually admits.