Friendships take time. And it makes sense that the more time you spend with someone, the more likely it is that you become friends. But how much time does it actually take to make a new friend? Researchers asked the same question, and their research was published last month in the Journal of Social and Personal Relationships

In a study entitled, How many hours does it take to make a friend?, author Jeffrey Hall explored what are known as “layers of friendship”: acquaintances, casual friends, friends and good friends. Hall wanted to identify how much time each layer of friendship takes.

So, he ran two studies. In the first, he asked 355 adults who had just relocated to identify a new acquaintance. The second study involved 112 college freshmen who had to identify two new acquaintances.

In follow-up interviews, Hall found that the more time people spent with their newly-found acquaintances, the more likely they were to develop into close friendship.

According to his research, Hall said it takes approximately 50 hours for a general acquaintance to turn into a casual friend.

90 hours bumped a casual friendship up to a bona fide friend. And over 200 hours spent together is how long it takes for friends to become good friends, or what we might call, best friends.

Of course, you can spend many more hours with coworkers and never become good friends. And that’s because a lot depends on how people spend time together. Meaningful, personal and enjoyable conversations help people grow closer together.

If you’re trying to make new friends, these numbers might help you gauge your current relationships and how you can take them to the next level.