Simple and compound interest

Simple interest

I = P.N.R

where:

I: Interest
P: Principal amount
N: Duration of deposit in years
R: Rate of interest (as in 0.73, not 73%)

So, the total amount after the deposit would be P + I.

Compound interest

I = P[(1 + i/(100*n))ⁿᵗ - 1]

where:

I: Interest
P: Principal amount
i: Rate of interest (as percentage. eg: 10%)
n: Compounding frequency (ie, number of compounding periods in a year)
t: Duration of deposit in years

Some differences

Simple Compound	Compound interest
No accumulated interest	Interest accumulates
Interest is calculated only once	Interest calculated periodically (eg: quarterly)
Benefitial for the borrower	Benefitial for the lender

References

Comparing quantities - NCERT class 8 Mathematics textbook
https://www.bankbazaar.com/fixed-deposit/compound-interest-formula.html