# Mathematical Formula - Interest Calculation

Simple interest is money you can earn by initially investing some money (the principal). A percentage (the interest) of the principal is added to the principal, making your initial investement grow.

n = number of compounding periods.

i = periodic interest rate, expressed as a decimal.

PV = present value.

FV = future value or balance.

PMT = periodic payment.

S = payment mode factor (0 or 1) indicating treatment of PMT.

0 corresponds to End, 1 to Begin.

I = interest amount.

INTG (n) = integer portion of n.

FRAC (n) = fractional portion of n.

**Simple Interest:**

**Compound Interest without an odd period:**

**With simple interest used for an odd period:**

**With compound interest used for an odd period:**