The donut counter widget is a pie chart that shows the number and percentage of cards in each status.
This is an interactive widget, which means you can hover the mouse over a slice of the chart to see its value and click it to see the cards that influence that number.
Type of Donut counter
By default, a donut counter is based on active progress, that is, the status of the cards. It can also show all progress (include no scope cards), the work in progress (cards that started on time, late, paused, etc.), end date (overdue, due this week, etc.) and start date (starts this week)
Show donut value as
This will change how the values of the widget will be shown, there are two values available:
Count, this will show the absolute values of the cards in scope based on the unit of measure, it will be the number of cards when the unit of measure is set to cards.
Percentage, to show the relative percentage of the related cards compared to all cards in scope.
To change the unit format, sorting and other options, follow the steps in this article: http://help.placker.com/en/articles/3336494-dashboard-common-settings