A University of Kansas professor has defined the amount of time necessary to make a friend and how long it typically takes to move through different stages of friendship.
In a new paper published in the Journal of Social and Personal Relationships, Professor Jeffrey Hall found that it takes roughly 50 hours of time together to move from mere acquaintance to casual friend, 90 hours to go from that stage to simple "friend" status, and more than 200 hours to become "good friends".
This means time spent hanging out, joking around, playing video games and the like. Hours spent working together just don't count as much.
Coworkers can be still become friends, of course, but you need to spend time together outside of the workplace for it to happen.
"The amount of time and the type of activity shared with a partner can be thought of as strategic investments towards long-term belongingness needs," wrote Hall.
Give the people you like your time, hope they'll give you theirs, and stay focused on having a good time. Friendship will follow.