Exercise :: Compound Interest  Important Formulas

Let Principal = P, Rate = R% per annum, Time = n years.

When interest is compound Annually:
Amount = P 1 + R n 100 
When interest is compounded Halfyearly:
Amount = P 1 + (R/2) 2n 100 
When interest is compounded Quarterly:
Amount = P 1 + (R/4) 4n 100 
When interest is compounded Annually but time is in fraction, say 3 years.
Amount = P 1 + R 3 x 1 + R 100 100 
When Rates are different for different years, say R_{1}%, R_{2}%, R_{3}% for 1^{st}, 2^{nd} and 3^{rd} year respectively.
Then, Amount = P 1 + R_{1} 1 + R_{2} 1 + R_{3} . 100 100 100 
Present worth of Rs. x due n years hence is given by:
Present Worth = x . 1 + R 100