Ooooo, I don't know if I'm just an odd ball but if I were to go by that chart, I'd be way off in left field in what supposedly fits me. I can almost fit 2 of me in a 16". I do use a 16" trail saddle sometimes because I like to put my 7 year old in front of me and ride together. Plenty of room. LOL!. Honestly, the same saddle size can feel different from saddle to saddle so it's best to try out at least the brand if you don't have the chance to try the actual saddle you're interested in. I'm 5'11" and weigh 125 lbs. And in my current barrel saddle, I ride a solid 14" and wouldn't go a hair over that. I've also owned a 15" Tex Tan that I still mourn over because it fit me beautifully but it didn't fit my horse. The Tex Tan was deeper which is why the 15" worked. I have sat in a 15" Billy Cook and would have probably liked at least 1/2" down from that. 15" would have probably worked though if there were no other options. So, just to be safe, either trial sit a few specific brands or be sure the saddle you're interested in is in front of you before you decide on a good size. In my case I had to trial sit saddles for stirrup length as much as seat size. I had to walk away from a local custom built barrel saddle on display at my feed store because the stirrups were on the last hole and I didn't want to risk it. I like to have a few holes to go to in either direction.
Don't forget they make half sizes too. If there's a few fingers width between you and the saddle, that's what you want. Most brands measure about the same, but not all of them. I would sit in a few to be sure. Posted via Mobile Device
For Western Pleasure, my daughter rode in a 15-15.5" saddle. For barrel racing, she rides in a 14". She has a little growing room, and if I thought she'd stop growing anytime soon, I would have gotten her a slightly smaller saddle for barrels, but as she averages 3-6" a year and the doctors think she'll grow for another 2 years, I didn't want to be buying a new saddle in each of the next 2 years. Barrel saddles should fit smaller than a typical western saddle.
That being said, I took her to a saddle shop and had her sit in several different barrel saddles/brands/sizes until I had a decent idea of what would fit her best in each brand. I made sure the person helping us was experienced in saddle fitting too.
I also want to add that everyone has their own personal preferences.
Some barrel racers should technically have a 15" seat; yet they ride in a 14" or a 14.5" because they like that close contact. Or vice versa: You might have a barrel racer who should be using a 14" seat, but you find them riding in a 15" seat because they like the extra room.
A good rule of thumb is that when you are sitting relaxed in the saddle, you should be able to fit two fingers between your thigh and the swell.
That's a good point to start with, but again, everyone like a different "feel" to their saddle so they could go up or down from that point.
Height and weight might also have nothing to do with it. Someone might be fit and light, but have really muscular thighs, therefore requiring a larger seat size. Or someone might carry all their weight around their belly, but have little legs, and therefore need a smaller seat size.
Again, you can make a generalized guess on height and weight, but there's always going to be differences in body type that can make a difference.
Best thing is to go to a tack shop and sit in a lot of different sized saddles and figure out the size that feels the best for you.