You may be aware that the official Apple Store app allows you to see the actual size of the Apple Watch cases by placing the iPhone on your wrist, giving you a rough idea of how big they are. However, holding the iPhone may not be that helpful which is where this new printable PDF comes in.
“I’ve created a PDF from screenshots of the actual size Apple Watch cases in the Apple Store app, scaled so, when you print it, the images are the correct size. It’s two pages, one with the 38mm watch, the other with the 42mm watch. Print them out, cut them if you want, and you’ll see exactly how big the cases are.”
While you print the PDF document, just keep in mind the trick is to get your printer to print a document at actual size, similar to the iPhone 6 / 6 Plus printable mockups from last year.