Part to whole relationships

To show:

  • ratio
  • percentage
  • proportion
  • share
  • breakdown
  • make up
  • hierarchy

Bar charts and pie charts should be used to show part to whole relationships.

Pie charts should only be used when there are less than six categories, otherwise use a bar chart or, if appropriate, combine categories.

Rank the categories in a pie chart and start the first segment at the 12 o’clock position.

Segments of a pie chart must sum to 100%. If the categories do not sum to a meaningful whole, do not use a pie chart. Where appropriate categories can be combined to highlight a certain message but should never be removed.

Example of pie chart ranked by size of category

All main categories included
A pie chart showing six categories of religion, with the largest section for Christianity.

Religion categories combined
A pie chart showing three combined religions categories, with the largest section for Religion stated.

Example of incorrect use of pie chart with categories removed

No religion and not stated categories removed

If no categories are dominant use a bar chart to illustrate your data.

Example of bar chart where no categories are noticeably dominant

A bar chart showing categories in descending order, where a single category is not noticeably more dominant than the others.

Example of incorrect use of pie chart where no categories are dominant

A pie chart where all categories appear to to be the same size, as there are only minimal percentage differences between them.

Multiple part to whole

Use bars to enable comparisons to be made across multiple part to whole charts.

Example of bar chart used to compare multiple part to whole

To enable comparisons within sub-categories

A rotated bar chart with categories stacked to show the part to whole breakdown.

To enable comparisons across sub-categories

A rotated bar chart with individual categories listed on the y axis and bars for the sub-categories grouped together.