How Many Slices Should a Pie Chart Have?

One question determines whether your pie chart succeeds or fails: how many slices? Too few, and you're not showing enough detail. Too many, and the chart becomes an unreadable rainbow mess. This short guide gives you the definitive answer backed by data visualization research and practical experience.

Why the 2-6 Rule Exists

Pie charts rely on the human visual system's ability to compare angles and areas. Research shows we can accurately distinguish between roughly 5-7 discrete segments before our perception breaks down. Beyond that threshold, slices become too similar to compare visually, colors become hard to distinguish, and labels start overlapping.

At 2-3 slices: Comparisons are instant. The chart communicates in a single glance.
At 4-6 slices: Still clear, but viewers need a few seconds to process all relationships.
At 7+ slices: Visual comparison fails. Viewers resort to reading every label individually.

What to Do When You Have More Than 6 Categories

Real-world data doesn't always cooperate with visualization best practices. When you have 8, 10, or 15 categories, you have three options:

1. Group Small Slices into "Other"

This is the most common solution. Identify categories that represent less than 5% of the total and combine them into a single "Other" or "Miscellaneous" slice. This keeps your chart clean while acknowledging the long tail of your data.

Best for: Market share analysis, budget breakdowns, survey results where a few categories dominate.

2. Switch to a Bar Chart

Bar charts can handle dozens of categories by extending vertically. They're also better for precise comparisons. If you're exceeding 6 slices, this is often the better choice.

Best for: Rankings, comparisons, or any scenario where you need to show all categories without grouping.

3. Create Multiple Pie Charts

If your data naturally divides into subcategories, use separate pie charts for each group. For example, "Revenue by Product Category" as one chart and "Mobile Revenue by Product" as a second.

Best for: Hierarchical data or drill-down analysis.

The Special Case of 2 Slices

Two-slice pie charts are valid but sometimes unnecessary. If you're showing "Yes: 70%, No: 30%" or "Completed: 85%, Remaining: 15%", consider whether a simple statistic or progress bar would be clearer. Pie charts shine when comparing three or more categories. For binary comparisons, simpler visualizations often work better.

When 2 slices work well: Comparing two distinct things (e.g., "Mac vs. PC market share") where the part-to-whole relationship matters.

Quick Decision Chart

• 2 slices: Consider if pie chart is necessary, or use a simpler format
• 3-4 slices: Perfect for pie charts—instant clarity
• 5-6 slices: Still good, ensure colors are distinct
• 7-8 slices: Group smaller slices into "Other" or switch to bar chart
• 9+ slices: Do not use a pie chart—use bar chart or table