Use the formula: A = P(1 + r/n)^(nt)
A = future value or total amount
P = principal or initial amount
r = annual interest rate in decimal form
n = number of times interest is compounded per year
t = time in years
To find compound interest earned, use: Compound Interest = A – P
Convert the interest rate from percent to decimal by dividing by 100
Substitute the values into the formula
Calculate the value inside the parentheses first
Raise the result to the power of nt
Multiply by the principal amount
Subtract the principal from the total amount to get the compound interest
For continuous compounding, use: A = Pe^(rt)