What is the formula of principal, rate, time to find interest?

Simple Interest (S.I) is the method of calculating the interest amount for some principal amount of money.

Simple Interest = $\frac{(P \times R \times T) }{100}$

Where,

P = Principal amount

R = Interest rate (in %)

T = Time duration (in years)  

Compound interest (or compounding interest) is interest calculated on the initial principal, which also includes all of the accumulated interest from previous periods on a deposit or loan.

Compound Interest = Amount – Principal

Where the amount is given by:

$A=P\left(1+\frac{r}{n}\right)^{n t}$

Where:

$A=$resulting amount (future value)

$P=$amount of principal (present value)

$r=$annual interest rate

$n=$number of compounding periods per year

$t=$time (in years)