Class Width Calculator

Your details

The smallest value in your dataset.
The largest value in your dataset.
How many bars (intervals) you want in the histogram. Typically 5-20. Use Sturges' rule as a guide.
The number of data points. Used only to compute Sturges' rule suggestion. Leave blank if unknown.
Class width
5

Exact class interval: range divided by number of classes

Range45
Rounded class width5
Sturges' rule: suggested classes6
Sturges' rule: suggested class width7.5
Exact class width5
Rounded class width5
Sturges' suggested width7.5

Class width is 5.0000 (rounded: 5.0000)

  • Your data spans a range of 45.0000, divided into 9 classes gives each bar a width of 5.0000.
  • Your chosen number of classes (9) aligns well with Sturges' suggestion of 6 for a sample of 30.
  • A class width that is too wide hides the shape of the distribution; one that is too narrow creates jagged, hard-to-read bars. Aim for 5-20 classes for most datasets.

Next stepOnce you have the class width, build your class intervals starting from the minimum value and add the class width repeatedly to find each boundary.

 = Powered by OnlyCalculators