Mobile users spend about 30 minutes a day on Facebook. Nobody else is even close

The number of monthly average mobile users for each social network in the U.S., and the total mobile minutes spent on each network every day in the U.S.. Based on those two numbers, the average mobile Facebook user spends about 30 minutes each day interacting on the social network. Snapchat is a distant second, with 8.5 minutes.

http://www.businessinsider.com.au/mobile-user-engagement-with-social-media-2016-4