Notes on FI/RE math and how to think about your own numbers.
The 4% rule turns a year of spending into a retirement number. Where it comes from, why retiring early breaks it, and a calculator.
September 7, 2026 · Updated October 11, 2026 · 4 min read
Barista FIRE means leaving full-time work years early and letting part-time income cover the gap. How the math works, plus a calculator.
September 7, 2026 · Updated October 11, 2026 · 4 min read
Lean FIRE retires on less than you spend today, chubby and fat FIRE on more. How big the gap in dates is, with a side-by-side calculator.
September 7, 2026 · Updated October 11, 2026 · 3 min read
Moving somewhere cheaper lowers what you need to retire and raises what you can save. Why it works twice, plus a calculator.
September 7, 2026 · Updated October 11, 2026 · 3 min read
What "coast FIRE" actually means, how to tell if you've hit it, and why the number that matters isn't your net worth.
August 23, 2026 · Updated October 12, 2026 · 3 min read