Many people don't think twice about the chair they sit in for hours every day, and employers often buy the same chair for everyone. But office chairs are not one size fits all — a six-foot-two employee won't find an ergonomic fit in a chair set up for a five-foot-two coworker. Height and weight are the two biggest factors, and the settings on your chair are how you account for them.
The short answer: to adjust an office chair, work from the floor up. Set the seat height so your feet rest flat with knees at about 90 degrees, set the seat depth so two to three fingers fit behind your knee, position the lumbar support in the curve of your lower back, lower the armrests until your shoulders relax, and finish with the tilt tension. The order matters, because each setting changes the next.
Key takeaways
- Start with seat height: feet flat on the floor, knees bent about 90 degrees, thighs roughly level.
- Seat depth should leave a few inches between the back of your knees and the seat edge while you lean against the backrest.
- Lumbar support belongs in the inward curve of your lower back; add a cushion if your chair has none.
- Armrests should support your forearms with relaxed shoulders and elbows near 90 degrees.
- If adjustments and accessories can't get you into a correct posture, the chair is the wrong size for you.
This guide focuses on the settings themselves. If you're choosing a new chair rather than adjusting the one you have, start with the complete guide to ergonomic chairs.
How Do You Adjust an Office Chair Step by Step?
Adjust in this order: seat height, seat depth, lumbar support, backrest angle, armrests, and tilt tension. Sit all the way back in the chair before you begin, and recheck earlier settings as you go.
| Step | Setting | Quick check |
|---|---|---|
| 1 | Seat height | Feet flat on the floor, knees about 90°, thighs roughly parallel to the floor |
| 2 | Seat depth | Two to three finger widths between the seat edge and the back of your knee |
| 3 | Lumbar support | Firm, even contact in the curve of your lower back — not your mid-back |
| 4 | Backrest angle | Slightly reclined, around upright to a few degrees back, while you type |
| 5 | Armrests | Forearms supported, shoulders relaxed, elbows near 90° |
| 6 | Tilt tension | Chair reclines with light effort and returns you upright without pushing |
What Is the Correct Office Chair Height?
The correct office chair height lets your feet rest fully on the floor with roughly a 90-degree bend at your knees. Check your leg position the next time you sit down, and raise or lower the seat until your thighs are about level and there's no pressure under them.
If your chair can't reach the right height, accessories can help:
- Need a little more height? A seat cushion may be enough. The Adjustable Seat/Back Cushion comes with customizable foam inserts and works on the seat or the backrest.
- Feet don't reach the floor? A footrest gives your feet the platform they need. The Workrite 215-Wide Footrest adjusts in height and tilt to support your feet at the right angle.
Remember that raising the seat to reach your desk can leave your feet dangling — that's when a footrest becomes essential rather than optional. If you're under about 5'4" and still can't get your feet flat, our guide to the right office chair for short people explains the alternatives.
How Should Seat Depth Be Set?
Set seat depth so you can lean fully against the backrest while leaving a few inches — about two to three finger widths — between the back of your knees and the front of the seat. Seat depth works hand in hand with seat height to put your legs in the correct position.
If the seat is too deep, you'll either perch forward and lose back support or sit back with the seat edge pressing behind your knees. If your feet still dangle after you've adjusted the seat height, a seat that's too deep is often the hidden cause. Not every chair has a seat slider; if yours doesn't and the depth is wrong, it's a sign the chair doesn't fit your body.
Where Should Lumbar Support Be Positioned?
Lumbar support should sit in the inward curve of your lower back, roughly at belt level, and press in firmly enough that you can sit upright without effort. Lower back pain is common among people who sit for hours, and even a correct seated position can't relieve all the stress sitting puts on your spine.
That's why many office chairs come with built-in lumbar support. Slide it up or down until it meets your curve, and adjust its depth if your chair allows it. If your chair has no lumbar support, add a back cushion that supports the natural curve of your spine. The Better Back Lumbar Cushion is designed to cradle your lower back and promote healthy spinal alignment on your existing chair.
How High Should Armrests Be?
Armrests should be just high enough to support your forearms while your shoulders stay relaxed and your elbows bend near 90 degrees. If they push your shoulders up, lower them; if you have to lean to reach them, raise them or move them closer.
Armrests that are too high or too wide are one of the most common causes of neck and shoulder tension we see. If they prevent you from pulling close to your desk, lower them below the desk edge or remove them.
How Do You Set Backrest Angle and Tilt Tension?
Set the backrest upright to slightly reclined for typing, then adjust the tilt tension so the chair supports you when you lean back without forcing you forward. A chair that moves with you encourages the small posture changes that reduce stiffness over the day.
If your chair has a tilt lock, use it sparingly. Being able to rock and recline between tasks is part of what makes a chair ergonomic. Once the chair is set, check your desk and monitor height so you don't undo your chair adjustments by reaching or craning.
What If Your Chair Still Doesn't Fit?
After inspecting and adjusting your chair, you may find the fix is simple — lowering the seat or adding lumbar support. If an accessory or adjustment won't do the trick, try switching chairs with a coworker; your chair may simply be better suited to someone else. Finally, invest in a new chair that meets your requirements.
When you're shopping, look for the controls this guide relies on: seat depth adjustment, lumbar that adjusts in height and depth, and multiple sizes. If you're weighing premium mesh chairs, see our comparison of a premium alternative to the Aeron. If you'd rather have a chair built to your measurements, read an in-depth look at the Sitmatic GoodFit.
Recommended Products for Adjusting Your Chair
Want an Expert to Check Your Setup?
Adjusting a chair by feel takes trial and error; having a trained eye watch you sit takes minutes. Our specialists adjust chairs for clients at our Palo Alto showroom and through virtual assessments, and we can tell you quickly whether your chair can be adjusted to fit or whether it's the wrong size. Questions about a specific chair? Contact our team.
👉 Request an Ergonomic Evaluation | Browse Back Cushions
Frequently Asked Questions
How do I adjust my office chair correctly?
Start with seat height so your feet are flat and knees are about 90 degrees, then set seat depth, lumbar support, backrest angle, armrests, and tilt tension in that order. Each change affects the others, so recheck earlier settings once you've finished.
How high should my office chair be?
High enough that your feet rest flat on the floor with your knees bent about 90 degrees and your thighs roughly parallel to the floor. If that height leaves you too low for your desk, raise the chair and add a footrest rather than letting your feet dangle.
What is the correct chair posture?
Sit all the way back with your lower back supported, feet flat, knees near hip level, shoulders relaxed, and elbows bent near 90 degrees at your sides. Your head should balance over your shoulders rather than leaning toward the screen.
Should my feet touch the floor when sitting in an office chair?
Yes — or rest on a footrest. When your feet dangle, the seat edge presses into the back of your thighs, which can restrict circulation and make it harder to sit back against the lumbar support.
What if my chair doesn't have lumbar support?
Add a lumbar cushion that supports the natural curve of your lower back and position it at about belt level. If you need precise control over firmness, an adjustable air lumbar cushion lets you fine-tune the support.
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This article shares ergonomic guidance based on our fitting experience and is not medical advice. If you have persistent or worsening pain, numbness, or tingling, talk to your doctor or physical therapist.
About the Author
Anne Kramer writes for Ask Ergo Works, where our ergonomic specialists have been fitting chairs and workstations from our Palo Alto showroom for more than 30 years.
