What are Pie Chart and Donut Chart and When to Use Them

The following chart shows the breakup of Full Time Employees by region at HSBC (As per Annual Report 2015)

When to use it

The primary use of a pie chart is to compare a certain sector to the total. The pie chart is particularly useful when there are only two sectors, for example yes/no or queued/finished.

Donut Chart

A Doughnut Chart or Doughnut Graph is a variant of the pie chart, with a blank center allowing for additional information about the data as a whole to be included. Each point is specified by an arc that length is proportional to the circumference as the data value to the total sum of all values.

The same chart above can be presented as a donut chart as shown below:

Advantages

The pie chart provides an instant understanding of proportions when few sectors are used as dimensions. When you use 10 sectors, or less, the pie chart keeps its visual efficiency.

Disadvantages

It is often hard to compare the results of two pie charts with each other, and therefore you should not do it.

It may be difficult to compare different sectors of a pie chart, especially a chart with many sectors.

The pie chart takes up a lot of space in relation to the values it visualizes.