The calculators
Three tools, one growth model. Pick the question you're trying to answer.
Compound Interest Calculator
Project monthly-contribution growth year by year, with an inflation-adjusted view.
Retirement / FIRE Calculator
Find your FIRE number and how many years of contributions it takes to reach it.
Coast FIRE Calculator
See how much you need saved today to coast to retirement on growth alone.
Built to be trusted
No black boxes, no accounts, no data leaving your browser.
Type, don't tap “Calculate”
Every input recalculates the result instantly. Drag a slider or type a number and the projection moves with you.
Formulas in plain sight
Each calculator documents the exact math it runs, in plain language, on the same page as the tool itself.
Private by design
Your numbers never leave the browser. Saved scenarios live in local storage on your device. Nothing is uploaded.