Do you appear younger than you actually are? Or do you already look like a withered old bag at the ripe old age of 27? Either way, Microsoft’s new website called How-Old.net will let you know.

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The new website, which Microsoft unveiled this week while kicking off Build 2015, lets you upload a picture that it will use to deliver an estimate of how old you are. Sometimes the estimate will be off, but usually only by a decade at most. You should also expect to get different estimates with different pictures, so don’t be depressed if Microsoft tells you you’re 10 years older than you really are on the first try.

Microsoft explains how it put together this seriously addictive website in a very short period over at its Machine Learning blog.

“The Face API has a demo page that uses the API to detect and extract information about faces in a photograph,” Microsoft explains “We found the ability of the face API to estimate age and gender to be particularly interesting and chose this aspect of it for our project. To make the experience more fun we used the face API alongside the Bing Search API from the Azure marketplace to create http://how-old.net. “

Check out the website for yourself by clicking here.