I got a big ass head and I only use the 2 end buttons. That would be 7 7/8. And you can just count down from there. 1 button is a 8 More on reddit.com

I've a vintage hat marked 7 1/8 that measures 22" around the inside of the sweatband. It also fits my 7 1/8 size head perfectly, just like all of my other vintage 7 1/8 hats. There has been no shrinkage. However, according to all different websites size 7 1/8 is anywhere from 22 1/4" to... More on thefedoralounge.com

This is one of the best things I’ve seen on here. More on reddit.com

My advice is try on as ordering is a minefield even when you know your fitted size. I was 7 3/8 for years then the last one I ordered didnt fit right and I had to spend a lot of time shrinking it with water and steam, it now fits perfectly but the fabric isn't like a new hat now, lint sticks to it easier. If I was to do it over again I'd order a 7 1/4 as well and send back the one that didnt fit but I thought I knew my size. From reading posts on here it seems lots of others have had issues with the same size hats fitting differently. Also, are snapbacks one size now? as mine say inside either small med or med large. small med with hair grown out i use 4 snaps loosened, but on windy days or after a haircut i might use 3. My med large i rarely wear bc i think i seem to be again in between sizes on that one. 3 snaps loosened is a bit loose but 2 loosened is slightly tight. Though what i think is loose is how i see many people wearing hats now where the brim is almost flat and you can fit 2 fingers under the space in front your ear. I guess it's fine for a poker player but I hate loose hats with flat brims it looks corny to me and it will fall off. If the hat fits properly the brim will acquire a nice gentle curve on its own. Anyway I digress, the point is that small med and med large are different, for me as a guy who takes either 7 3/8 or 7 1/4 it's a difference of a snap, and in med large i use 3 snaps loosened and small.med 4 snaps loosened. Basically 3 empty snaps on the med large feels close to the 7 3/8 i just got when it arrived, possibly a smidge tighter but still looser than after I shrunk the fitted one quite a bit with steam. So i would think one snap loose seems to be 7 on med large, 2 snaps 7 1/4, 3 7 1/4 and so on but i could be wrong. To me fit is everything with clothes but even more so with hats which is why i recommend trying on is the best way ar least for your first fitted. Or if you cant get to a store id be ordering 2 sizes to return one. Even if they charge you (think fanatics charge 10 to return) it would be better because if the hat doesnt fit you either will have to send it back anyway or deal with a poorly fitting hat which sucks. The reason i rarely wear the med large snapback is my small med fits perfectly as do my 2 on field fitteds and I can't deal with even a tiny bit too much tightness or looseness. It wasn't a total waste of money but I only wear it for DIY, painting, etc. With a too tight hatyou get sort of 'head fatigue' similar to the ear fatigue of wearing bulky over head headphones that are tight. Too loose and a gust of wind can make your hat blow off and you also wont get the nice gentle curve in the brim that forms to your head when a perfectly fitted hat is worn. And you can't run down fly balls in the outfield. More on reddit.com