Free Calculator

Compound Interest Calculator

Calculate compound growth on any investment. Add monthly contributions, set the compounding frequency, and see how much of your balance is pure interest.

Your Investment Details

Initial investment ($)

Annual interest rate (%)S&P 500 historical average ≈ 10% nominal, 7% real

Time period (years)

Monthly contribution ($)Optional — added to principal monthly

Compounding frequency

MonthlyQuarterlyAnnually