Seat depth adjustment

Seat depth adjustment lets the seat pan of a chair slide forward or backward independently of the backrest, changing how far the front edge sits relative to your knees. It solves a problem that seat height alone cannot fix, since people with shorter or longer thighs need a different seat length to sit comfortably against the backrest.

The target gap between the front of the seat and the back of your knees is usually about two to three finger-widths. Too little gap and the seat edge presses into the back of the knee, restricting circulation over a long session. Too much gap and there is no thigh support, so the lower back loses contact with the lumbar support.

Not every chair offers this adjustment, and it is often left out of budget mesh chairs in favor of the more commonly advertised seat height and armrest adjustments. Shoppers who are notably shorter or taller than average benefit the most from checking whether seat depth adjustment is included before buying an ergonomic office chair, since it is harder to work around later.