Compound Interest Calculator
See how your investments grow with the power of compound interest. Includes optional monthly contributions.
Year-by-Year Growth
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How Compound Interest Works
Compound interest means you earn interest on both your original principal and on accumulated interest. The formula is: A = P(1 + r/n)^(nt) + C × ((1+r/n)^(nt) − 1) / (r/n), where P is the principal, r is the annual interest rate, n is the number of compounding periods per year, t is the number of years, and C is the periodic contribution.
About this Calculator
Compound interest is the eighth wonder of the world — this calculator shows you exactly why. Enter your initial investment, regular contributions, interest rate, and time horizon to see how your money grows exponentially. Visualize the power of compounding and understand why starting early makes such a dramatic difference.
Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.