Coast Fire Calculator

Most retirement math asks when you can stop working. Coast FIRE asks the quieter, earlier question: when can you stop saving? Because compound growth doesn't need your help forever — once your pile is large enough, it will reach your number on its own, and every dollar you contribute after that point only buys an earlier or richer retirement, not the retirement itself. That moment is the crossover between two curves: your pile if you keep saving, and the 'coast number' — the smaller pile you'd need at each age so growth alone finishes the climb by retirement. This lesson makes both visible. Drag the sliders and watch the teal line (you, still saving) rise to meet the amber bar (the coast number, rising toward your target): where they cross is the age you could downshift, take the lower-paying-but-better job, or go part-time without touching your retirement. It reframes the whole project: you don't have to save all the way to your number — you only have to save until growth can take it the rest of the way.

Free and interactive — no sign-up, nothing to install. Read the full lesson for the plain-language explanation.