The digital point, I believe, is exactly 1/72 of an inch and the metal Anglo-American point is slightly larger. For most purposes you can set short amounts of text on the computer and have it come out fairly closely to the computer version when using the same point size. The differences can be noticeable, however. On a 36 page poetry chapbook I ended up with a few poems running over the page size, adding two unplanned pages to the book. I only had enough type to print a couple of pages at a time. Unfortunately I didn't discover the problem until about half done. Adding two pages to the back also added two blank ones near the front. I solved that problem by commissioning a student artist to draw a frontis piece at the last minute. Now I'm a bit more careful when mocking up my work by computer.