The average bathroom vanity ranges from 30 to 36 inches in height. Because of the influx of families sharing bathrooms after World War II, the normal countertop standard height measurements were on the lower end to accommodate everyone. In the industry, the accepted standard height of a bathroom vanity is 30-32 inches.
Comfort height refers to making the counters higher to accommodate taller people or provide a more comfortable reach for those who may worry about back problems from too much leaning. Because the standard kitchen counter is 36 inches and proves to be a productive workspace, many people are choosing to update their bathrooms to match. Therefore, if you see a vanity sized at comfort height, it probably measures 36 inches.
And, of course, there are also many sizes in between, including everything from 31 inches to 35 inches, depending on the style and vanity that you ultimately choose.