--- title: "Pie Chart Overload" summary: "Eight near-identical slices no human eye can rank. A bar chart was right there." poke: "Eight slices, three of them the same size. Nobody can read this. A bar chart could." category: "Chart-Type Abuse" severity: 3 tags: ["pie chart", "part-to-whole", "comparison"] badChart: "pie-overload-bad" fixedChart: "pie-overload-fixed" date: 2026-08-05 citations: - key: fewpies note: "“Save the Pies for Dessert” — the definitive, free takedown of the overloaded pie." - key: clevelandmcgill note: "Their ranking shows angle and area are judged far worse than position along a scale." - key: junkcharts note: "Kaiser Fung’s running #onelesspie campaign exists for precisely this chart." - key: datatoviz note: "Pie charts are the first entry in its catalogue of caveats." --- ## The sin The pie chart asks the reader to compare **angles** — something people are genuinely bad at. One or two slices, fine. But eight slices, several of them within a percentage point of each other? Nobody can tell whether Firefox beats Samsung by eyeballing two thin wedges on opposite sides of the circle. ## Why it deceives Angle and area are hard to judge precisely, and slices scattered around the circle can't be lined up against a common baseline. The small categories blur into an indistinguishable fringe, and the ranking — usually the whole point — becomes guesswork. ## The repentance Use a **sorted horizontal bar chart**. Every value shares one baseline, the ordering is explicit, and long labels sit comfortably beside their bars. Reserve the pie for the rare case of two or three parts of an obvious whole — and even then, a bar chart rarely does worse.