I was asking about guiar stools before

Depends how and where the stool is being used.

Actual "guitar stools" are those dimensions for a reason.  The height of the chair is so that you're not too high, but not so low that you look stupid compared to the others who are standing around you; on a stage that is. 

The bar is the perfect height for most so that when you place one foot on it, that leg is perfectly angled for your guitar to sit on.  Your other leg is at a nice, slightly downward angle to the floor.  This makes for a very, very comfortable acoustic guitar playing position for those of us who need or prefer to sit while playing.  They also swivel for the convenience of moving around to grab stuff, or get your floor leg to a pedal etc.

Until I got my first guitar stool, playing on stage was always awkward as just about every other kind of stool I tried had some sort of flaw that made it uncomfortable; like too tall, or too short, no swivel, no bar, or etc.

Now for personal use only, that's a whole different story.  The stool can and probably should be literally anything and built any way you want it.  You're not on stage so it doesn't matter what you look like or how high you are. 

If you want it close to the floor so that the floor is your "bar" then go for it.  If you want the stool to be very high like a tavern/bar stool to get up and out of the way of stuff that may be around in your main playing areas, then go for it.  Or anything in between.  For personal use, I don't think there's any wrong way, it's all about what you personally prefer.

But ya, the typical "guitar" stool is designed that way with a specific purpose in mind.  I love, love, love my guitar stool and would almost be lost without it on stage.  But at home, I just play on my couch or my computer chair.  Don't even use a stool at home.

I have a stool I custom built before I got a "proper" one.  It's a bit higher than the typical guitar stool because I didn't know how high it should be and just took a guess.  It works, it's got a bar for my leg and all, but I never use it.  It's a bit too high for on stage (floor leg is at an uncomfortable angle because it's a bit too high) and I have no use for the height at home.  It now serves as a very small table I usually have a duffel bag sitting on.  lol.

Just my nickels worth. 

How wide are these round seats? I find 14" for most and it took a while because most list just the height.

Well I gathered the wood , had enough to make a seat 1 1/2" thick form 4 sections and and glued that together. Made 4 top sections to fit between the legs out of 3/4" pine board ripped them to 3" wide. Made 4 legs out of 2x2's and found some 7/8" dowel that I will use for the bottom of the legs to stabilize them. I just made the legs straight no angle so they are wider at the bottom like most are. The seat will be 15" in diameter. The 2x2's I sawed one edge smooth the I need to sand the other three since they are rough plus use a hand plane to put a 45 degree bevel on the legs edges. Just going to glue and screw the legs to the top sections and to the seat and cut the dowels drill holes in the legs and just glue them in place.

Took me longer to clean up all the saw dust from the table saw and miter saw. I have a router thought I'd round over the top of the seat edge, if it does not make a huge mess or I'll just do it with a hand plane. None of my old power tools have dust collection other than the miter saw and that does not catch it all. My old belt sander and random orbital do have dust collection that work pretty well.

I just made it 18" tall seems it will work fine for me.

Not sure, never actually measured it.  It's at my church so I can't measure it now, but....

*holds hands about 14" apart, looks and ponders*........

Ya, that sounds about right. 

ancient1,  Wow, those are really short.  The question that immediately comes to my mind is:
Why do people need such a short chair at a nail salon?  I've passed many and glanced in and they all look like they're sitting at normal height; from my outside vantage point anyways.

I honestly don't get why this is specifically a nail salon chair.  lol.

I made it the same height as two wooden chairs we have both are 18" at the seat. I used to use them and they worked fine for me. I know it seems short yet it will work/ Once if ever I get the damn thing done I post photo's. Have to wait for the glue to dry then sand it and used some water based clear on it.