Proper office chair setup means adjusting seat height, depth, lumbar support, and armrests so your feet rest flat and your spine keeps its natural curve.
The goal is simple: the chair works around your body, not the other way around. UCLA Health’s office ergonomics guidance notes that most adjustments come down to a few key points — seat height, seat depth, lumbar support, backrest angle, and armrests. Work through them in order, and the chair will feel noticeably different.
What Height Should Your Office Chair Be?
Set the seat height first because everything else depends on it. Stand in front of the chair and raise or lower the seat until the highest point sits just below your kneecap. Sit down and check that both feet rest flat on the floor — or on a footrest if the chair won’t go low enough.
Your knees should bend at about 90 to 110 degrees, with your thighs roughly parallel to the floor or your hips slightly higher than your knees. If your feet dangle or pressure shifts to the front of your thighs, the seat is too high. If your knees push up past your hips, it’s too low. Both positions strain your lower back over a full workday.
How Much Seat Depth And Backrest Angle Do You Need?
Seat depth comes next. Slide forward until your back touches the backrest, then check the gap behind your knees. Any less and the seat edge presses into your calves; any more and you can’t use the backrest without perching forward.
Then adjust lumbar support so it sits in the small of your back, around your belt line, supporting the natural curve of your lower spine.
For the backrest angle, most guidance lands between 90 and 110 degrees, with some sources allowing up to 120 degrees.
Armrests And Workstation Position: The Final Adjustments
Armrests are the most common source of shoulder pain. Set them so your shoulders stay relaxed and your elbows sit close to your torso, with forearms supported and roughly parallel to the floor. If the armrests are too high, they lift your shoulders; too wide or too far forward, they block you from pulling the chair close to the desk. Some guidance simply recommends removing armrests if they prevent proper desk proximity.
After the chair fits, adjust the workstation itself. You should be able to sit back against the backrest while reaching your keyboard and mouse — not lean forward or perch on the front edge. Keep frequently used items within easy reach and position the monitor about an arm’s length away, with the top of the screen near eye level.
| Adjustment | How To Set It | Common Mistake |
|---|---|---|
| Seat height | Seat top just below kneecap; feet flat, knees at 90–110 degrees | Too high — feet dangle, pressure on thighs |
| Seat depth | 2–3 finger widths behind the knees | Too deep — edge presses into calves |
| Lumbar support | At the small of the back, belt-line area | Too low — lower back curve unsupported |
| Backrest angle | Slight recline, 90–120 degrees | Rigid upright posture strains the spine |
| Armrests | Elbows close to torso, shoulders relaxed | Too high or wide — shoulder elevation |
| Feet | Flat on floor or footrest | Dangling or tiptoeing compresses thighs |
One important caveat: a chair is only “ergonomic” if it can be adjusted to fit your body. Two people can sit in the same model and need completely different settings. Re-check your adjustments after working for a while — bodies settle, and fine-tuning after an hour of use is normal. If you’re shopping for a new chair and want one that handles these adjustments comfortably, our roundup of the best armchair office chairs covers tested models worth considering.
What Is The Best Way To Sit In An Office Chair?
Use the backrest’s recline rather than holding an upright posture, and let the lumbar support carry your lower back’s curve. Shift position occasionally; no single posture is meant to last all day.
References & Sources
- UCLA Health. “Chair Setup.” Provides the recommended 110-degree backrest angle and general chair-fitting guidance.