A social tipping process is a large change in a social group that can be started by few people. Does the 80/20 rule apply here? We see if this is the case for human social groups. We find that, if the social conditions allow, change occurs when around 25 % of people engage. While tipping can happen between 10 % and 43 %, most cases tip by 40 %. However, tipping is not guaranteed: when people are resistant, trusted friend groups and context-appropriate messaging help the process along.