When should I use a double bar graph instead of a single bar graph

You should use a double bar graph when you want to compare two sets of related data side by side for the same categories. In a double bar graph, each category has two bars placed next to each other, each bar representing one data set.

This is helpful when you want to show:

• Before and after data (e.g., marks scored before and after extra classes)
• Two different groups (e.g., boys vs. girls, two different schools, two years)
• Comparisons over time (e.g., sales in 2024 vs. 2025)

Example: If you want to compare the marks of boys and girls in five subjects, a double bar graph shows both sets of marks clearly next to each other for each subject, making the comparison easier.

A single bar graph, on the other hand, is used when you only have one set of data to display for each category.