Both bar charts and pie charts can be used to show proportion, which expresses a partial value in comparison to a total value.

Bar charts express quantities through a bar’s length, using a common baseline Pie charts express portions of a whole, using arcs or angles within a circle Bar charts, line charts, and stacked area charts are more effective at showing change over time than pie charts. Because all three of these charts share the same baseline of possible values, it’s easier to compare value differences based on bar length.