Real-world social networks exert an enormous influence over our attitudes about marriage. This is one reason that Facebook makes some people so unhappy. Watching the parade of our friends' major life events makes us both envious and lonely.
Given that envy and loneliness are Valentine's Day's two chief exports, TIME presents an app that analyzes your Facebook feed to see exactly when your friends are tying the knot—and when it might be time for you to take the plunge.
This application measures the median age of your married friends, meaning the person for whom half your married friends are younger and half are older. Because you are probably friends with a lot of people close to your age, this figure will theoretically identify whether you have passed the point where many of your contemporaries start tying the knot. It will work better for some than others.
For the purposes of this tool, "married" refers to anyone who lists his or her relationship status as "married," "engaged," "in a domestic partnership," or "in a civil union." We're aware that some people use this status facetiously. Since the distribution of your friends' ages tends to form a bell curve centered on your own age, a few jokesters shouldn't throw off the figure drastically.
This app only counts friends who list their date of birth, including the year. In testing, TIME found that this amounted to about 25 percent of all profiles, but that will vary from user to user.
Many people who are not in a serious relationship simply do not list a relationship status. It is not possible to distinguish these people from those who are married but choose not to report that fact to Facebook. As a result, the percentage of married friends that this app reports is probably lower than the actual figure, though not by a huge margin.