Calculate how your investment grows over time with compound interest. See the power of compounding on your savings or investments.
Compound Interest Calculator
Financial
Inputs
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Enter your starting principal (initial investment amount).
Input the annual interest rate offered by your bank or investment.
Set the time period in years you plan to keep the investment.
Select how often interest compounds (monthly is most common).
Click Calculate to see your final amount and total interest earned.
Compound interest is calculated using the formula A = P(1 + r/n)^(nt), where P is the principal, r is the annual rate, n is compounding periods per year, and t is the time in years. Unlike simple interest, compound interest earns returns on previously earned interest — creating exponential growth over time.
Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus all previously accumulated interest, leading to exponential growth.