How FIRE Works

The math is straightforward: the less you spend and the more you save, the sooner your investments can cover your expenses. Many FIRE followers use the 4% rule: if you have 25 times your annual expenses invested, you may be able to withdraw 4% per year. That doesn't mean you have to quit work — it means you have the option to.

People often use labels to describe their approach. Lean FIRE means targeting a lower budget in retirement. Fat FIRE means a higher one. Coast FIRE means saving enough early so that without adding more, growth could get you to your number by a chosen age. Barista FIRE means covering part of your expenses with part-time or flexible work. Our calculators (FIRE, Coast FIRE, Lean FIRE, Barista FIRE) help you model these paths.

We provide calculators and dashboards so you can see your numbers and scenarios. We don't tell you how much to save or when to retire. Use our FIRE calculator to estimate your potential FIRE date, then adjust inputs and compare. Your decisions are yours; our job is to make the math clear.