How to Read Pie Charts:

  1. Larger slice = bigger proportion - Visual size matters
  2. All slices = 100% - The whole pie represents the total
  3. Read percentages - Don't just rely on visual estimation
  4. Compare to identify dominance - Which category is largest?

Donut Charts (Pie Chart Variation)

A donut chart is a pie chart with the center removed, creating a ring shape.

75%

Donut Chart

Can display total/summary in center

Regular Pie Chart

Solid circle, no center space

When to use donut vs. pie: Both work equally well. Donut charts can look more modern and allow you to display a total or key metric in the center.

Pie Chart Best Practices

✅ DO

  • Use for 3-6 categories maximum
  • Order slices from largest to smallest
  • Include percentages on or near slices
  • Use distinct colors
  • Label each slice clearly
  • Ensure all slices add to 100%

❌ DON'T

  • Use for more than 6 categories (too crowded)
  • Compare multiple pies side-by-side
  • Use 3D pies (distorts perception)
  • Use exploded slices (hard to compare sizes)
  • Use for precise comparisons
  • Use for showing change over time

When NOT to Use Pie Charts

Pie charts are often overused. Here are better alternatives:

❌ Too Many Slices (>6 categories)

Problem: Hard to distinguish small slices

Better alternative: Bar chart - easier to compare many categories

❌ Comparing Multiple Pies Side-by-Side

Problem: Can't easily compare slices across pies

Better alternative: Stacked bar chart or grouped bar chart

❌ Showing Change Over Time

Problem: Pie charts are snapshots, not trends

Better alternative: Line chart or stacked area chart

❌ Precise Comparisons

Problem: Hard to visually compare slices of similar size (is 23% bigger than 21%?)

Better alternative: Bar chart with values labeled

🎯 Practice Exercises

Exercise 1: Choose the Right Chart

For each scenario, decide: Line chart or Pie chart?

  1. Monthly website traffic for the past year
    Show Answer

    Line chart - Shows change over time (trend)

  2. How your $500 monthly budget is divided among 5 expense categories
    Show Answer

    Pie chart - Shows part-to-whole proportions for few categories

  3. Comparing revenue of 3 products over 4 quarters
    Show Answer

    Multiple line chart - Shows trends over time for multiple series

  4. Market share of 10 smartphone brands
    Show Answer

    Bar chart (NOT pie) - Too many categories for pie; bar chart allows better comparison

Exercise 2: Spot the Mistakes

Identify what's wrong with these chart uses:

  1. Using a line chart to compare sales across 8 different product categories (not time-based)
    Show Answer

    Mistake: Line charts are for continuous/time data. Categories should use bar charts.

  2. Creating a 3D pie chart with 12 slices
    Show Answer

    Mistakes: (1) Too many slices (max 6), (2) 3D distorts perception. Use bar chart instead.

  3. Comparing 3 pie charts side-by-side to show how budget changed over 3 years
    Show Answer

    Mistake: Hard to compare across pies. Use stacked area chart or line chart for trends over time.

📝 Knowledge Check

Test your understanding of line and pie charts!

1. What type of data is best suited for line charts?

2. What is the maximum recommended number of slices for a pie chart?

3. You want to show how your company's revenue changed month-by-month over the past year. Which chart should you use?

4. What does a pie chart best represent?

5. Why should you avoid using more than 5-6 lines on a single line chart?

6. What's the main problem with 3D pie charts?

7. You need to compare quarterly sales for Products A, B, and C over 2 years. What's the best chart?

8. In a pie chart, all slices should add up to what percentage?

Question 9: Why should you avoid using pie charts when you have more than 5-6 slices?

Question 10: When showing trends over time, what is the advantage of a line chart over a column chart?

← Previous: Bar & Column Charts Next: Scatter & Area Charts →