Percentage Calculator – WAST Calculator

Percentage Calculator

Please enter the required values ​​below and click "Calculate" to get your answer.

What is % of

is what % of

Percentage Change Calculator

Please enter "New Number" and "Old Number" below, select "Increase" or "Decrease", and click "Calculate" to get the percentage change.

Percentage Difference Calculator

Please enter "Value 1" and "Value 2" below and click "Calculate" to get the percentage difference between the two numbers.

What is WAST Percentage Calculator?

WAST Percentage Calculator is a percentage calculator tool used to calculate different types of percentage calculations. This tool is created by Snehasis Samanta and Susobhan Roy.

What is a percentage??

In mathematics, a percent is a ratio or number that represents a fraction of 100. A percentage is a way of expressing the dimensionless relationship between two numbers. Other methods include ratios, fractions, and decimals. It is widely used in daily life to express marks, possibilities, etc.

Percentages are often expressed with a “%” sign after the number. Can also be expressed by writing “percent” or “pct” after the number. For example, 27% means 0.27,  27 pct, or 27/100.

Percentages are calculated by multiplying the ratio value by 100. For example, if there are 35 boys out of 50 students in a classroom, the ratio value is 0.7, which is multiplied by 100 to get the percentage of boys in the classroom.

0.7 x 100 = 70%

In other words, the ratio of 35 boys to students in the class is equal to 70% of the students in the class.

Formula to Calculate Percentage

By Percent formulas we can find the percent or division of a whole in terms of 100. Using this formula, we can express numbers as fractions of 100.

Formula to Calculate Percentage:

Percentage = (Value / Out of Value) × 100

Example: (45 / 70) × 100 = 64.28% or 64.28 percent

How to Calculate Percentages?

There are many formulas that are used to calculate percentage problems. The most basic of them can be considered as A / B = C x 100. There are all mathematical variations of this formula below.

(Here A and B are numbers and C is percentage)

Let’s see three basic percentage problems.

  • What is C% of A?
  • What % of A is B?
  • Find A, if C % of A is B?

Problem 1: How to calculate percentage of a number. Using formula: C% x A = B

Example: What is 35% of 130?

Let, B is 35% of 130.


  • C% = 35%
  • A = 130
  • B = ?

∴ Calculation,

  • B = C% x A
  • Or, B = 35% x 130
  • Or, B = (35 / 100) x 130
  • Or, B = 0.35 x 130
  • Or, B = 45.5

Ans. So, 45.5 is 35% of 130.

Problem 2: How to find what percent of A is B. Using formula: (B / A) x 100 = C%

Example: What percent of 130 is 50?

Let, C% of 130 is 50.


  • C% = ?
  • A = 130
  • B = 50

∴ Calculation,

  • C% = (B / A) x 100
  • Or, C% = (50 / 130) x 100
  • Or, C% = 0.38 x 100
  • Or, C% = 38%

Ans. So, 38% of 130 is 50.

Problem 3: How to find A, if C% of A is B. Using formula: B / C% = A

Example: 60 is 25% of what number?

Let, 60 is 25 % of A

Or, 25% of A is 60


  • A = ?
  • C% = 25%
  • B = 60

∴ Calculation,

  • A = B / C%
  • Or, A = 60 / 25%
  • Or, A = 60 / (25 / 100)
  • Or, A = 60 / 0.25
  • Or, A = 240

Ans. So, 60 is 25% of 240.

Percentage Change

Percentage change is calculated when the value of a quantity changes over a period of time. The rate of change is calculated as the rate of increase and the rate of decrease.

To calculate the percent change, divide the change in value by the original value and multiply the resulting value by 100.

  • Percentage Increase
  • Percentage Decrease

How to Calculate Percentage Increase?

Percentage increase refers to the rate of change of a value that increases over time. For example, increase in population, increase in number of bacteria on surfaces, etc.

The increase rate can be calculated using the following formula:

Percentage Increase = [(New value – Old value)/Old  value] × 100

How to Calculate Percentage Decrease?

Percent decrease refers to the rate of change of a value that decreases over time. For example, less rainfall, less covid cases. The rate of decline can be calculated using the following formula:

Percentage Decrease = [(Old value – New value)/Old value] × 100

Percent Difference

The formula for the percentage of the absolute value of change is dividing by the average value and multiplying by 100. Remember, “percent” means 1/100.

The topic is very important and constitutes the main topic. Some questions in most competitive exams.

Among the different types of percentage questions, one of the most common questions is percentage-difference formulas. This article explains the difference percentage formula with solved example.

Percentage Difference Formula

As mentioned above, the percentage difference is calculated by dividing the absolute value of the change by the average value and multiplying by 100.

Percentage Difference = [(a – b) / {(a + b) / 2}]  x 100

where a and b are two different values.

You can use this formula to find the percent difference between any two values. Note that the order of the numbers does not matter because the change (difference) of the values ​​takes an absolute value.