I posted this a few months ago, but it's not easy to find on my blog anymore so here it is for you again in a downloadable format to save to your computer or pin in your workspace.
I've been using the numbers for six years now so feel confident that they work. But everybody's different, so please comment below if you've found measurements that work better or differently for you. And if size really matters to you, be sure to measure the mattress or pillows (length, width & depth) of the specific bed you have. It's remarkable how different they can be.