How do I know what height of bar stool to buy?
Answers:
30" is probably fine (considering how specific it is haha) but be sure the height is to your liking...some people like to be right on top of the bar while others prefer a bit of a sunk-in feeling. the most important thing is to avoid the dreaded knee bang! leave plenty of room, and consider any foot rests on the bar or stool when making a decision...hit the stores!
Other answers:
30"
30"
If your bar is the same height as your counters, then the shorter one, if it's taller than you need the taller one. Usually there are only two sizes.
Consider first how far a fall you're willing to take when snockered and sitting on the bar stool. I think it's better to install a low bar counter, maybe 18" above the floor and have bean bag chairs for yourself and guests. This configuration and design is very drinking-friendly and one can easily roll off the bean bag (if desired) and prone out on the floor without injury.
the standard bar stool height is 29 inches, which should fit your bar perfect.
The idea is to have at least 12" clearance between the seat top to the underside of the counter top.