The standard seat height for a dining room chair is usually between 18 and 19 inches to ensure a comfortable fit under standard dining room tables, which are approximately 30 inches high. It's recommended that you leave a space of about 10 to 12 inches between the underside of your table and the top of the chair seat to allow for leg room. This distance helps to prevent feeling cramped and makes it easier to sit comfortably around the table.