Other than the common formula and also rule of 72, these are useful formulas too ...
Compound Interest Future Value
FV = PV * ( 1 + i )N
PV = present value
FV = future value (maturity value)
i = interest rate in percent per period
N = number of periods
Annuity
FV = PMT * [ ( ( 1 + i )N - 1 ) / i ]
FV = future value (maturity value)
PMT = payment per period
i = interest rate in percent per period
N = number of periods
Simple Interest Amortized Loan Formula
PV * ( 1 + i )N = PMT * [ ( 1 + i )N - 1 ] / i
PMT = the payment per period
i = interest rate in percent per period
PV = loan / mortgage amount
N = number of periods
