Read a Double Bar Graph

How to Read a Double Bar Graph

A double bar graph compares two related data sets across the same categories. Each category has two bars, often shown with different colors or patterns, so you can compare values quickly.

1) Identify the parts

• Read the title to know what the graph is about.
• Check the labels on the horizontal axis to see the categories.
• Look at the key or legend to match each bar style with the correct data set.
• Read the vertical scale to know what each bar height represents.

2) Read each bar carefully

For a chosen category, find the two bars and note their heights using the scale. If the value is between marks, use the spacing shown on the axis to estimate correctly.

3) Compare the data

You may be asked to:

• tell which value is larger,
• find the difference between the two bars,
• compare totals across categories.

To find a difference, subtract the smaller value from the larger value.

4) Simplify the final answer

If the question asks for a comparison or difference, write the result clearly and simplify it. Make sure your answer matches the units shown on the graph.

5) Check your work

• Does your answer use the correct category and bar color/pattern?
• Did you read the scale accurately?
• Does the final comparison make sense from the graph?

A careful reading of the title, key, and scale usually prevents mistakes.