# Compound Interest Calculator See how savings or investments grow over time — with optional regular contributions and any compounding frequency. Live results, all in your browser. ### How it works Compound interest earns interest on your interest. The starting amount grows by `P(1 + r/n)nt`, where *r* is the annual rate, *n* the number of times it compounds per year, and *t* the years. Regular contributions are added each compounding period and grow as an annuity. All maths runs on your device — nothing is sent anywhere. --- *Source: [ocxly.com/compound-interest.html](https://ocxly.com/compound-interest.html) — OCXLY, free 100% client-side privacy-first tools. Free compound interest calculator. See how savings or investments grow over time with optional regular contributions and any compounding frequency. Runs entirely in your browser.*