Statistics

Class Width Calculator

Find the class width for a frequency distribution.

Calculated Output

Class width 13

Formula: width = ⌈(max − min) ÷ classes⌉

Step-by-Step Breakdown

1. Values used:

2. Maximum value = 98

3. Minimum value = 12

4. Number of classes = 7

6. Class width = 13

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The math behind it

width = range ÷ number of classes, rounded up to a convenient whole number.

Range 12–98 in 7 classes → width 13.

How many classes should I use?

Often 5–20; a common rule is √n classes.