Get Standard Computer Desk Height PNG. That's what determines the standard desk height. The edge of the seat should not contact the back of your knees.
While average desk height varies a bit, most desk heights range between 29 and 30 from the floor to the tabletop.
Ideally you should get an adjustable height desk because that would offer you more freedom when it's important to use the right type of desk for the right type of work. Typical desk height affects the way your desk fits the room and how it fits you. That's what determines the standard desk height. So the new standard is 26″ and it works both for laptops and desktop computers.