If you’ve ever wondered how old you look in pictures, Microsoft has just developed an addictive new website that offers the answer. The site, how-old.net, takes data from an uploaded image to determine the subject’s age and gender.

According to Microsoft’s Machine Learning blog, the project started as a simple experiment among Microsoft engineers. They were “playing around” with new face detection software and decided to ask a couple hundred people to try it out and tell them what they thought. Within hours, the experiment had reached 30,000 people curious about whether a simple Internet site could accurately read their face.

Using existing Microsoft APIs, or application program interfaces, the engineers combined a program that detects information about faces in a photograph with tools that embed search results and location data.

Don’t sweat it if the site gets your age wrong—different pictures elicit different results, so you can always try again.

This article originally appeared on Time.com.