FIRE Path Planner — When Can You Stop Working?
Save 25× your spending and you're done?
The 4% rule was built for a 30-year retirement. Retire at 40 and your money has to last 50 years or more — and a bear market could hit the year you quit.
In this example, the 4% rule says age 54. After simulation, you need until 60 to be 90% sure.
What you get
- Earliest retirement age: the first age at which your money lasts to 95 in at least 90% of 2,000 simulations. Have a target age? You get its success rate and how much more to save each month.
- FI number and Coast FI: how much the 4% rule says you need, and whether what you have now would reach it by 65 even if you stopped saving.
- Sequence-of-returns risk: how much your success rate drops if the first 3 years of retirement are a bear market.
- Levers: spend 10% less, save 5% more, cut only retirement spending, or lower fees — how many years each one saves.
- Savings-rate table: years to financial independence at savings rates from 10% to 70%.
Who it's for
Anyone who wants to know when they can be financially independent, is planning to retire early, or wants to know how much more to save each month. Any country, any currency; pensions and big costs like children's education can be added.
How to use
- Download from Capafy — you get a zip file (no need to unzip).
- In Claude, turn on code execution, then upload the zip under Settings → Skills. (Claude Code users: unzip into ~/.claude/skills/.)
- Describe your situation in plain English. Claude asks for the numbers it needs, runs the model, and walks you through the results.
Output and language
Claude explains the results in your language. The Excel workbook and written report are currently labeled in Traditional Chinese; English labels are planned for a future version.
Privacy
Runs locally in your own Claude environment. No external connections, no API keys, and your numbers never leave your machine.
Requirements
A Claude environment that can run Python (e.g. Claude Code, or Claude with code execution enabled). Uses openpyxl; Claude can install it on first run.
Disclaimer
Simulations use assumed returns and don't predict actual performance; pension and tax rules vary by country. For personal planning only — not investment, tax, or legal advice. No financial products are recommended.
