QQuickKit

Compound Interest Calculator

See how compound interest grows your money. Enter principal, annual rate, years and compounding frequency to calculate your final balance.

About This Tool

Compound interest is one of the most powerful forces in personal finance. Unlike simple interest, compound interest earns returns on previously earned interest — making your savings grow exponentially over time. Enter a principal, annual rate, number of years and compounding frequency to see your final balance and total interest earned.

Features

  • ✓Four Compounding Frequencies — Choose annually, semi-annually, quarterly or monthly compounding.
  • ✓Principal vs Interest Breakdown — Visual bar shows how much of the final balance is earned interest.
  • ✓Long-term Projection — Works for any time horizon — from 1 to hundreds of years.
  • ✓Zero Rate Support — Handles 0% rate correctly (no growth scenario).

FAQ

What is the compound interest formula?
A = P(1 + r/n)^(nt), where P = principal, r = annual interest rate (decimal), n = compounding periods per year, t = time in years.
How does compounding frequency affect growth?
The more frequently interest compounds, the faster your balance grows. Monthly compounding yields slightly more than annual compounding at the same rate, because interest earned earlier starts earning interest sooner.
Does this account for taxes or inflation?
No. This is a gross calculation. Real returns are affected by taxes on interest income, inflation eroding purchasing power, and fees. Use this as a planning reference, not a financial projection.

Further Reading