Your Friendships Peaked at 25. Three Million Phone Records Say So.

If your friendships feel like they are slowly thinning out, you are not imagining it, and you are not doing anything wrong. You are just past 25.

In one of the largest studies of its kind, researchers at Aalto University and Oxford analysed the mobile-phone records of around three million people, and found a strikingly consistent shape. The number of people we are in regular contact with climbs through our teens and early twenties, peaks at about age 25, and then declines, steadily, for the next two decades.

The peak is earlier than anyone wants it to be

Twenty-five. That is the top of the mountain. After that, on average, the circle quietly contracts. Men and women follow almost the same curve.

This is not a story about people getting worse at friendship. It is a story about a life filling up. Careers, partners, kids, mortgages, moves: each one is good, and each one quietly crowds out the loose, low-stakes time that friendships need to survive.

Your social circle does not collapse after 25. It just stops growing by accident, and starts requiring a decision.

What actually changes

Before 25, friendship mostly happens to you. After it, you have to build the structure that used to be built for you. The people who stay richly connected into their thirties and forties are not the lucky ones. They are the ones who kept one or two things that repeat: a standing dinner, a Sunday game, a weekly table.

The research is here if you want the curve, and The Conversation puts it plainly.

So if you are over 25 and the group chat has gone quiet, nothing has gone wrong. The free hours just ran out. The fix is now in your hands, which it was never going to be while it was still automatic.