How do I get game hardware requirements?

What's a good way to get a games minimum & recommended hardware requirements?

My game just got greenlit and they require me to set a recommended and minimum hardware requirements but I have no idea what to type in them. Is there a good software/website that can calculate it?

If you're running a high end computer which can run your game with ease, you can run a virtual machine and reduce it's specs until the game does not play properly anymore.