Compound Interest Calculator

This compound interest calculator uses the standard formula A = P(1 + r/n)^(nt): enter a principal amount, an annual interest rate and a number of years, pick how often interest compounds — yearly, half-yearly, quarterly or monthly — and it instantly shows the maturity amount and the total interest earned. Everything recalculates live as you type, with no submit button and no sign-up.

Compounding frequency matters more than most people expect, because each compounding period adds interest on top of previously earned interest. Take ₹1,00,000 at 8% per annum for 10 years: compounded yearly it grows to about ₹2,15,892, compounded quarterly to about ₹2,20,804, and compounded monthly to about ₹2,21,964. Same rate, same time — the only difference is how often the interest is credited. Switching the compounding option in the dropdown lets you see that gap for your own numbers in one click.

The calculation runs entirely in your browser, so the amounts you type are never uploaded or stored on a server, and the page keeps working offline once loaded. It models a one-time lump sum — the way bank fixed deposits, bonds and single investments actually behave — which makes it a quick, private way to sanity-check the maturity value a bank or advisor has quoted you before you commit.