Table of Contents
What Is a Pie Chart?
A pie chart is a circular graph divided into slices that represent proportions of a whole. Each slice's size corresponds to the category's percentage of the total. Pie charts are best used when showing the composition of a whole, such as market share, budget allocation, or survey results with a small number of categories.
While simple to understand, pie charts are most effective with 2-7 categories. With too many slices, the chart becomes difficult to read. For more categories or precise comparisons, bar charts may be more appropriate.
Formulas
Best Practices
- Limit to 7 or fewer categories for readability.
- Start the first slice at 12 o'clock position.
- Order slices from largest to smallest.
- Use contrasting colors for adjacent slices.
- Label percentages directly on or near each slice.
- Avoid 3D effects as they distort perception of slice sizes.
Example Breakdown
| Category | Value | Percentage | Angle |
|---|---|---|---|
| Marketing | 30,000 | 30% | 108° |
| Development | 40,000 | 40% | 144° |
| Operations | 20,000 | 20% | 72° |
| Other | 10,000 | 10% | 36° |
Frequently Asked Questions
When should I not use a pie chart?
Avoid pie charts when comparing values across time (use line charts), when you have more than 7 categories, or when differences between slices are small and hard to distinguish visually.
Do all slices have to add up to 100%?
Yes. A pie chart represents parts of a whole, so the percentages must sum to 100% (and angles to 360 degrees). If your data does not represent a complete whole, a different chart type is more appropriate.
What is a donut chart?
A donut chart is a pie chart with a hole in the center. It offers the same proportional information but allows additional data or labels to be placed in the center space. Both chart types follow the same mathematical calculations.