While working on a side project recently, I needed a way to help users quickly understand how their savings could grow over time. Nothing fancy — just input a principal, an interest rate, and a timeframe, and see the future value. But here's the thing: I didn't want to spin up a server, manage a database, or deal with API rate limits. I wanted something that would work instantly, even on a slow connection, and that wouldn't cost me a cent in hosting.
So I built a compound interest calculator that runs entirely in the browser. No backend. No dependencies. Just pure JavaScript and a bit of math.
The "Why Not Just Use an Existing Tool?"
Good question. There are plenty of compound interest calculators out there. But most of them are either:
Buried in a finance website with a million other widgets
