Simple Interest

I = Prn

F = P + I

I = Interest earned

P = initial amount of money borrowed

r = Rate of simple interest

n = Number of time periods

F = Final balance

Reducible Interest

Balance owing = P + I - R

It is called reducible interest because the interest is based on a steadily decreasing principle.

Future value (FV)

FV = PV (1 + r)ⁿ

FV = Future value of the loan

PV = Present value of the loan

r = Rate of simple interest per period

n = Number of compounding time periods

I = Interest (compounded) 

PV = FV / (1 + r)ⁿ

FV = Future value of the loan

PV = Present value of the loan

r = Rate of simple interest per period

n = Number of compounding time periods 

Compound interest

A = P (1 + r)ⁿ

^{A= Amount owing}

P = Initial amount

r = Rate of interest per compounding period

n = Number of compounding time periods

Daily = Annual interest rate/ 365

E = (1 + r)ⁿ - 1

E = Effective rate of interest p.a

r = rate of interest

n = number of periods