The concept of percentage is best suited to find out the rate of change when two or more than two quantities are attached to each other by any common relationship.
It is a way to express a number as a fraction of 100.  It is denoted by using the sign “%”. For example 50% is equal to $\frac{50}{100}$ or 0.5.

Percentage calculator will help us to calculate the percentage of given set of numbers.
  
The following are the steps to calculate the percentage of any numbers. 

What is x% of y?

$\frac{x \times y}{100}$

It can also be seen that x% of y = y% of x

y is what % of x?

$\frac{y \times 100}{x}$