Pie chart: definition, examples, and best practices.

What is a pie chart?

A pie chart represents a whole as a circle, then divides that circle into slices sized in proportion to each category's share. It is one of the oldest and most recognisable chart types precisely because the concept needs no explanation: a bigger slice means a bigger share, and all the slices together make up the full circle.

It is also called a circle chart, though pie chart is by far the more common name. The type works well only when there are few enough slices that each one stays comparable by eye.

A worked example

A finance team breaking down FY26 planned operating costs by category might use data like this.

When to use a pie chart

• Breaking down operating costs by category when one or two categories clearly dominate the total.
• Showing a simple market share snapshot for a small number of named competitors.
• Presenting the result of a single-choice survey question with five or fewer answer options.
• Highlighting that one category makes up the majority of a total, when that dominance is the whole point.

When not to use a pie chart

• If you have more than five or six categories, a stacked bar chart keeps every slice readable.
• If several slices are close in size, a bar chart makes the small differences between them far easier to compare than a pie chart can.
• If you want a headline number visible in the middle of the shape, use a donut chart instead.

How to read a pie chart

Start with the largest slice and work around the circle from there, usually clockwise from the top. Slice size, not the exact angle, is what the eye judges best, so lean on data labels for precise figures rather than expecting the reader to estimate percentages from the shape alone.

Best practices

• Cap the number of slices at five or six. Beyond that, group the smallest categories into an "other" slice.
• Order slices by size, largest to smallest, starting from the top and moving clockwise.
• Add data labels with the percentage or value on each slice, since angle alone is hard to judge precisely.
• Avoid 3D effects or exploded slices. Both distort the reader's perception of relative size.
• Never use a pie chart for values that can go negative. Negative slices have no sensible visual meaning.