Yeah, that's what I'm measuring.

Geez, I guess I'm going to have to try on another ball cap to see if it fits at all

Actually, I think I know what the problem was for me. My head is so large that the edge of a baseball cap wouldn't come down far enough, so it wouldn't even get to the largest part of my cranium If it had, I'm sure the band would have run out of notches. So I now remember why I don't weat hats like that. They make me look like I'm wearing a beenie with a rim