Definition of Daily Active Users (DAU)

Question

Suppose there exists an application X.

Is DAU defined as either (a) the number of users that login X every single day over a specified period, or (b) the average total number of users that login X each day over a specified period?

For example:

Specified period = 5 days

The same 50 users login X everyday. In addition, a random number of users login X on top of this each day, say 20, 40, 10, 25, 30.

Does DAU = 50 or DAU = (70+90+60+75+80)/5

Answer 1

DAU is how many unique users visit the site daily. In other words, DAU lives only during a specific day, and not other specific period.

In your example, DAU for the first day is 50 users, the socond - 70 users, the third - 90 and so on.

• DAU = (70+90+60+75+80)/5 is not a DAU, that is more likely an average value of DAU for 5 days;
• as wel as 50 is DAU for the first day only, not for whole 5 days.

If you wanna calculate an Active Users index for a specific period, you may user Weekly Active Users (WAO) and Monthly Active Users (MAO) or, let's say, a [5 days] Active Users counters.

To calculate "[N Days]AU", you should measure it by counting the number of unique users during a specific measurement period, such as within the previous N days.

So, if User1 (and no one else) logins to the site every 5 days, you'll still have [N Days]AU = 1 for the site, because you have only 1 unique active user during this period.