Office Chair Size Specifications

The size specifications of office chairs should be designed according to ergonomic principles to ensure comfort and health during use. The specific parameters are as follows:

Seat Height: Typically ranges from 40 cm to 50 cm (some standards recommend 380-450 mm), and should be adjusted according to the user's height. The key requirement is that when the feet are flat on the ground, the thighs should be parallel to the ground to avoid leg suspension or excessive knee pressure due to improper height.

Seat Width: The normal range is 45 cm to 55 cm. The standards for solid wood office chairs are more detailed: armless chairs should have a seat width of no less than 380 mm, while armrest chairs should generally have a seat width of no less than 460 mm (based on the inner width of the armrests, which should be 20-30 mm wider than the average shoulder width of about 400 mm to ensure shoulder relaxation).

Seat Depth: Generally ranges from 35 cm to 45 cm (some standards specify 400-450 mm). The depth should match the length of the thighs: too shallow will cause the thighs to suspend, increasing pressure on the buttocks; too deep may force the waist to lean forward, increasing the burden on the spine. The ideal state is to leave about a fist's distance between the back of the knee and the front edge of the seat.

Backrest-Related Dimensions:

• Height: Medium-back chairs usually do not exceed the waist, covering the area from the waist to the shoulders; executive chairs may extend to the head with more complex designs.
• Backrest Angle: The angle between the backrest surface and the horizontal line is generally 100°-106°, which can disperse spinal pressure and reduce fatigue from prolonged sitting.
• Total Height: Refers to the distance from the highest point of the backrest to the ground, which should be coordinated with the seat height to ensure natural head support.

Armrest Dimensions:

• Inner Width of Armrests: Should be 20-30 mm wider than the shoulder width (average shoulder width is about 400 mm) to avoid arm suspension or shoulder internal rotation.
• Armrest Height: Refers to the distance from the highest point of the armrests to the ground, which should match the height of the desk to allow the elbows to bend naturally at 90°-100°, reducing tension in the upper limb muscles.

Other Angle Parameters: The seat tilt angle (the angle between the seat surface and the horizontal plane) is generally 2°-5°. A slight backward tilt can promote a neutral pelvic position and improve sitting stability.

The above dimensions should be dynamically adjusted according to the user's body type. For example, taller individuals may need to increase the seat height and backrest height appropriately, while wider individuals may need to expand the seat width. Reasonable design can effectively prevent occupational diseases such as cervical and lumbar spondylosis and improve work efficiency.