The average bar stool measures 30 inches tall and fits a standard 42 inch high bar, according to Overstock, while counter-height bar stools average 26 inches tall and fit a standard 36 inch high counter. Extra-high bar stools average 34 inches tall, while table-height bar stools average 18 inches tall.
The industry standard calls for bar stools that measure between 9 and 13 inches shorter than the bar at which they are placed, according to interior designer Gail Mayhugh. Not all bars or counters are the standard height, so it is a good idea to measure the counter before shopping. Mayhugh advises planning for 26 to 30 inches of horizontal space between each seat.