A chairs seat is generally 11" shorter than the height of the tabletop. In your case you would need a 25" chair. luckily for you this is the 36" is the architectural standard for counter tops so all companies make a "counter height" stool with a seat height of 25".
Bar Height: 42"
Bar Stool: 31" seat h.
Counter Height: 36"
Counter Stool: 25" seat h.
Table: 28-29"
Dining Chair 17-18"h.