Part of a whole
Pie chart
Shows parts of a whole through sectors whose angles and areas follow their proportions.
- Chart
- Composition
- Share comparison
What it answers
How is a whole divided among a few parts?
- Shape
- Circle divided into sectors
- What it shows
- Dominant parts and broad composition.
Example: Nord Signal AB
The question
Which service brings Nord Signal most of its revenue?
Nord Signal revenue by service, 2025
Nord Signal AB is a fictional company created for Insyt.
The misleading version
Same question, drawn badly
Six slices with no values
What goes wrong. Six slices without values force readers to guess. The small slices run out of distinct colours. A sorted bar chart shows this better.
When to use it
Use it when
A few clearly distinct nonnegative components.
Avoid it when
Many similar slices, negative values or precise ranking needs.
How to read it
Read labels and compare sector shares of the full circle.
Note
Use nonnegative values and a meaningful total.
The data you need
- Layout
- Long table
- Fields
- Category: text; Value: nonnegative number
- One row is
- One component of a defined whole. What is the grain?
- Rules
- Use mutually meaningful components and a positive total. Values may be counts or shares. Check rounded percentages.
- Optional
- Series or Parent for multiple wholes. Do not mix totals with their components.
- Preparation
- Check nonnegative components, reconcile the represented whole and aggregate duplicate categories. Define whether records are counts or already normalised shares.
- Units
- Show counts or shares of a named whole. Share = component / relevant total; name that total and the population/period it covers.
Worked example
Values 32,40,28 total 100. Draw sectors 32%,40%,28%. B is the largest share at 40%.
| Category | Value |
|---|---|
| A | 32 |
| B | 40 |
| C | 28 |