## Basic Formulas of Compound Interest

If A = Amount

P = Principle

C.I. = Compound Interest

T = Time in years

R = Interest Rate Per Year

## Shortcut Formulas for Compound Interest

**Rule 1: If rate of interest is R1% for first year, R2% for second year and R3% for third year, then**

**Rule 2:**

If principle = P, Rate = R% and Time = T years then

**If the interest is compounded annually:****If the interest is compounded half yearly (two times in year):****If the interest is compounded quarterly (four times in year):**

**Rule 3: If difference between Simple Interest and Compound Interest is given.**

- If the difference between Simple Interest and Compound Interest on a certain sum of money for 2 years at R% rate is given then

- If the difference between Simple Interest and Compound Interest on a certain sum of money for 3 years at R% is given then

**Rule 4: If sum A becomes B in T _{1} years at compound interest, then after T_{2} years**