Compond Interest

School Formula

A = P(1+R/100)^t, where
CI = P[(1+R/100)^t-1]

P = Principal
R = Rate (in %) per year
t = Time in years

To convert to general formula, just take the rate per period and time in that period

Banking Formula

This is used since banks generally give out annual CI rates

A = P*(1+R/n)^nt, where

A = Final Amount
P = Principal
R = Rate (in decimal) per year
n = number of compounds per year
t = Time in years