The standard stipulates that the desktop height is 680-760mm, the sitting height is 400-700mm, the maximum sitting height of soft surface is 460mm (including subsidence), the height difference between desktop and seat surface is 250-320mm, the gap between chair and stool is more than 200mm, and the gap between them is more than 580 mm..
There is a standard to judge whether a set of tables and chairs is suitable for sitting. The correct height of tables and chairs should enable people to maintain two basic verticality when sitting: First, when their feet are flat on the ground, their thighs and calves can be basically vertical. At this time, the front edge of the seat cannot press the lower thigh plane. Second, when the arm hangs naturally, the upper arm is basically perpendicular to the forearm, and the height of the desktop should just touch the lower plane of the forearm. In this way, people can keep the correct sitting posture and writing posture.