If you, like me, have had trouble setting your media queries to exactly the right dimensions, then you will be as excited as I was to find websitedimensions.com. And if that isn't the most nerdy way of starting a post, I don't know what is!
I looked up screen dimensions of all the major devices and thought to myself – I am sure they cannot really achieve those dimensions. But all I needed to do was use the device's browser to load websitedimensions.com/pixel/ and everything was sorted out immediately.