How pie chart percentages and angles are worked out
Each slice is its value's share of the total, and a full circle is 360°.
share = value ÷ total × 100 · angle = value ÷ total × 360°
- Add all the values to get the total.
- Divide each value by the total and multiply by 100 for its percentage.
- Multiply the same fraction by 360 for its angle in degrees.
- Starting from percentages, multiply each by 3.6 for the angle. Anything under 100% is shown as Unallocated.
Worked example — Rent 1,800, Food 600, Transport 300 and Savings 300 total 3,000. Rent is 1,800 ÷ 3,000 = 60%, and 0.6 × 360° = 216°.
Common pie charts
| Values | Shares |
|---|---|
| 50, 30, 20 | 50% (180°) · 30% (108°) · 20% (72°) |
| 1, 1, 1, 1 | 25% (90°) · 25% (90°) · 25% (90°) · 25% (90°) |
| 45, 25, 15, 10, 5 | 45% (162°) · 25% (90°) · 15% (54°) · 10% (36°) · 5% (18°) |
| 1800, 600, 300, 300 | 60% (216°) · 20% (72°) · 10% (36°) · 10% (36°) |
| 2, 3, 5 | 20% (72°) · 30% (108°) · 50% (180°) |
Swipe the table sideways to see the rest.
Amounts. Each row is worked out by this calculator.
Things to consider
- Write one category per line, or separate them with commas: Rent: 1800, Food: 600.
- Keep to about six slices. Group small ones into Other.
- Order slices from largest to smallest so the chart reads easily.
- Use the percentage mode when you already have shares, such as survey results.
Frequently asked questions
How do I calculate pie chart percentages?
Divide each value by the total and multiply by 100. For 50, 30 and 20, the total is 100, so the shares are 50%, 30% and 20%.
How do I work out the angle for each slice?
Divide the value by the total and multiply by 360°. Rent of 1,800 out of 3,000 is 1,800 ÷ 3,000 × 360° = 216°.
How do I turn percentages into degrees?
Multiply by 3.6, since 100% is 360°. 25% is 90° and 10% is 36°.
Why do my rounded percentages add to 99.99% or 100.01%?
Each share is rounded on its own. Three equal slices are 33.333...% each, which round to 33.33% and add to 99.99%. The exact shares still total 100%.
When shouldn't I use a pie chart?
Avoid it with many small slices, or when slices are close in size and need comparing. A bar chart is easier to read then.
How do I make a pie chart in Excel or Google Sheets?
Put labels in one column and values in the next, select both, then choose Insert and Chart, and pick Pie. The sheet works out the percentages for you.
Results are estimates for general information only, not financial, medical or professional advice.