How would you estimate the number of monthly users for Dropbox?

Interesting Question.

Dropbox is the cloud storage platform where the users can store their data on the cloud similar to Google Drive right?

Interviewer: Yes

Does dropbox have any enterprise plan? Do you want the enterprise users included as well?

Interviewer: No, just the app users

Do you want the number for any target geographic location?

Interviewer: Let's take India

Estimating the number of monthly users of Dropbox:

Standard/Normal Account Users:

Total India Population - 1.3B

Smartphone users - 60% of Population = 0.6*1.3 = 780Mn

Usually Elders dont usually use any cloud storage, so eliminating 25% of the Smartphone users

= 780*0.75 = 585M

Dividing the Users based on the OS -> Android - 70%, iOS - 30%

As the iOS users majorly use iCloud -> Assuming 20% of iOS users are Dropbox users = 0.2*0.3*585Mn

Google Drive is the biggest competitor and assuming its market share among the android phones is 70%, only 30% of android users are dropbox users = 0.3*0.7*585Mn

Now we got the total users of dropbox.

To estimate MAU of dropbox = 30% of Total Users

= 0.3(35+122)= 47.2Mn Indian Users