Adjusting your office chair

Revised 2020.04.01

A common definition of ergonomics is to fit the task to the person. Your first step in setting up your computer workstation should be to adjust your chair to create your ideal working posture.
After that, set up the rest of the workstation so you do not have to deviate from that posture (e.g. lean forward, move elbow away from body, etc).
Though some sitting positions are better than others, there is no single position that should be used all day.

Many, including the CSA standard on office ergonomics, promote switching between different positions throughout the day. Some examples are below.
  • Reclined
  • Upright
  • Forward tilt

For all of the adjustments described below:

  • The adjustments are for computer use
    • Working postures can be task dependent [paperwork, typing, etc]
  • Assess fit after each adjustment.
  • Make note of any adjustment that is at the end of its range (max or min). The range of adjustment may not be sufficient. (e.g. Is your seat height at its highest or lowest setting?)

1. Before you sit, check to see which of these adjustments your chair has:

If your chair does not have all of the adjustments below, you may find some help in the Links section at the bottom of this page.

1.1. Seat angle lock & forward tilt stop
1.2. Spring tension (set to max)
1.3. Seat height (set it to max or just above knee height)
1.4. Seat depth (set it to min)
1.5. Backrest angle
1.6. Backrest height (and/or lumbar support height). On some chairs, the whole backrest moves up and down. On others, the lumbar support moves independently of the rest of the backrest.
Note: If there are no obvious knobs or levers to unlock backrest height, just try lifting it. This is how "ratchet" backrests work.
1.7. Lumbar support size (set it to max)
1.8. Armrest height (set to lowest)
1.9. Armrest separation (distance between armrests).
1.10. Armrest pad forward/back, swivel and/or sideways.

2. After sitting, adjust the following before moving close to your desk:

2.1. Seat height
  • Heels comfortably on the floor or footrest [to learn when a footrest may be required, see Links at the bottom of this page]
  • Torso-to-thigh angle greater than 90°
  • Knee angle greater than 90°
2.2. Seat angle
  • Unlock the seat angle (Warning: the seat may move suddenly)
  • Try leaning back
  • Adjust the spring tension if you find leaning back difficult
  • You may find it easier to adjust the seat angle if you lower your seat but be sure to return it to your preferred setting that you found earlier.
  • Lock the seat angle when you've found your preferred angle

2.3. Seat depth
  • With your bum all the way at the back of the seat, the gap between the front edge of the seat and the back of your knee should be 1-4 finger widths.
2.4. Backrest angle
  • 90° to 120° relative to the seat
2.5. Backrest and/or lumbar support height
  • Same height as the curve in your low back [lumbar curve]
2.6. The above steps are highly inter-related so you may have to repeat them a few times

2.7. Lumbar support size and/or shape
  • Adjust so that it provides comfortable support
2.8. Adjust forward tilt stop
  • You may have to unlock your seat angle and lean back to do this

3. If your chair has armrests

They should not interfere with your arm position, if you don’t want to use them.

3.1. Stand up so that you can assess your arm posture without potentially being limited by your chair armrests

3.2. Let your arms hang relaxed at your sides
  • Elbows close to your sides
  • Elbow angle approximately 90°
  • Wrists straight, fingers curled when typing
3.3. Move your hands closer together to assume a typing posture (i.e. thumbs touching)
  • If you notice your wrists bending sideways, a split keyboard may be helpful.

3.4. Sit down, while maintaining the arm posture you just established ["your ideal typing posture"]

3.5. Adjust the armrest and armrest pad position to support your arms in your ideal typing posture
  • Armrest height
    • Check that your forearms are supported without you having to lift your shoulders or lean to the side
  • Distance between armrest pads
    • Check that your elbows don't have move further away from your torso
  • Forward position of armrest pads
    • Check that the front edges of the pads are behind your wrists when your arms are in your ideal typing posture
    • This will ensure that the pads do not hit the desk when you are trying to sit close to your desk later