Ergonomic Chair Fitting: The Five Measurements That Matter

Seat height

Feet flat, knees at roughly 90 degrees, thighs parallel to the floor. Most chairs cover 16"–21", which suits users from about 5'2" to 6'2". Outside that range you need a specific short or tall cylinder.

Seat depth

Two to three fingers of clearance between the seat edge and the back of your knee. Too deep and the seat cuts circulation; too shallow and you lose thigh support. Adjustable seat depth is the single most under-rated feature on a task chair.

Lumbar position

The lumbar support should meet the inward curve of your lower back, not your mid-back. Height-adjustable lumbar matters more than depth-adjustable.

Armrest height

Shoulders relaxed, elbows at 90 degrees, forearms resting lightly. If armrests force your shoulders up, remove them — badly set arms are worse than none.

Recline tension

You should be able to lean back with light pressure and be held, not thrown. Set tension to your body weight, then use the tilt limiter to stop the recline where you want it.