Class Width Calculator

The class width calculator helps you determine the optimal width for classes or intervals when organizing the data into a frequency distribution or histogram. This helps in finding a balance between having too few classes (which may oversimplify the data) and too many classes (which may over complicated the patterns and trends).

How to use this class width calculator?

• Simply enter the values of minimum and maximum class boundaries into the given box

• Add the number of classes

• Hit on the Calculate button

• Our tool will process the information and show you the class width results along with step-by-step calculations

What is class width?

The difference between the upper limits of two consecutive classes or the lower limits of two consecutive classes in a data set is called the class width.

A class width is also known as the class interval. In statistics and data analysis, When organizing data into classes, it's important to choose a suitable class width that effectively represents the distribution of the data and the overall appearance of the histogram.

Too small class widths may result in an uneven histogram that does not effectively represent the basic patterns in the data. On the other hand, too large class widths may oversimplify the distribution and hide important details.

Class width formula:

The formula for calculating the class width is:

Class Width = (Max - Min) / n

Where,

• Max: The highest value in the dataset

• Min: The lowest value in the dataset

• n: The number of classes or intervals

How do I calculate the class width?

Using the formula we discussed earlier, you can easily calculate the class width. We also provide an example below to further clarify this concept.

Example:

Let’s say you have a dataset of test scores for 10 students, ranging from 65 to 95. The individual scores are as follows: 80, 75, 92, 88, 65, 95, 78, 82, 90, and 72.

And you want to divide them into 5 classes.

This is how you can determine the class width:

• Maximum score (Max): 95
• Minimum score (Min): 65
• Number of classes (n): 5

Calculation:

Add these values into the class width formula:

• Class Width = (95 - 65) / 5 
• Class Width = 30 / 5 = 6

In this example, the class width is 6. That means we can make 5 groups, each covering a range of 6 points to organize and study the exam scores in a helpful way such as:

• Class 1 —> 65-70
• Class 2 —> 71-76
• Class 3 —> 77-82
• Class 4 —> 83-88
• Class 5 —> 89-94

You can also adjust the number of classes based on your analysis goals and desired level of detail.