Daily Active Users

Daily active users, or DAU, is the number of unique users who performed the product's qualifying active action at least once during a calendar day.

The count is a unique count, so adding seven consecutive days does not produce weekly active users; someone who came every day appears once in the weekly figure. The day boundary matters too: changing the project timezone moves a late-night session into another day and reshapes the trend. Above all, the number is only as meaningful as the active definition behind it; if active means opening a page, the figure is large and of little value.