Charts & Visualizations

Pie Chart

A circular chart divided into sectors representing proportions of a whole.

Definition

Pie charts display data as slices of a circle, where each slice's size is proportional to the value it represents relative to the total. They are used to show part-to-whole relationships.

Examples

Device traffic distribution

Chart Visualization

This example includes an interactive chart visualization with 3 data points.

Chart type: pie

Usage

Best Used For

  • Showing composition of a total (few categories)
  • Displaying percentage distributions
  • Comparing parts to the immediate whole
  • Simple proportional comparisons (less than 6 categories recommended)

Data Requirements

[Object]

When to use this chart

Two-slice share only

Data shape: Paid vs organic revenue split (2–3 slices max)

Replace with horizontal bar when slices exceed three or precise comparison is required

Source: Cleveland & McGill (1984) — angle/area rank lowest for magnitude comparison vs bar length

Limitations

Important Considerations

  • ⚠Difficult to compare similar sized segments accurately
  • ⚠Not effective with many categories (use Bar Chart instead)
  • ⚠Can be misleading if not showing 100% of a whole
  • ⚠Takes up more space per data point than alternatives like Bar Charts

Best Used For

  • Showing composition of a total (few categories)
  • Displaying percentage distributions
  • Comparing parts to the immediate whole
  • Simple proportional comparisons (less than 6 categories recommended)

Supplemental Resources

Frequently asked questions

Common questions about Pie Chart, answered.

What is a pie chart?
A pie chart is a circular chart split into wedges, where each wedge's angle (and area) is proportional to its share of the total. It shows composition — how a single total divides into parts at one moment — such as traffic share by channel or budget split by platform. The whole circle represents 100%.
When should I use a pie chart?
Use a pie chart sparingly: when you have a single total, just 2–5 categories, and one clearly dominant slice or a simple 'this vs the rest' story. It works when the exact values matter less than the rough proportion. For anything more — many categories, similar-sized slices, or comparing parts precisely — a bar chart is easier to read because lengths compare better than angles.
Why do data experts dislike pie charts?
Because people judge angles and areas poorly compared to lengths. When slices are similar in size, it's nearly impossible to tell which is bigger without labels, and comparing across two pies is worse. Many slices become an unreadable rainbow. Pie charts aren't always wrong, but for accurate comparison a sorted horizontal bar chart almost always communicates the same data more clearly.
How many slices should a pie chart have?
Keep it to about 2–5. Beyond five, slices get thin, colors multiply, and the proportions blur. Group small categories into a single 'Other' slice, or — better for many categories — switch to a bar chart. If you find yourself adding data labels to every slice just to make it readable, that's a sign a bar chart would serve better.
Pie chart vs donut chart — is there a difference?
A donut chart is a pie chart with the center cut out. Functionally they're the same — both show part-to-whole via slice angle — and they share the same limitations. The hole can hold a total or label and some find it cleaner, but it doesn't fix the core readability issues. Choose either for a simple 2–5 category split; choose a bar chart when precise comparison matters.

Related Terms

Donut Chart

Related term

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Treemap

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Stacked Bar Chart

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Data Visualization

Mentioned in

Articles from the AdSights blog that discuss Pie Chart.