Adjusting an office chair starts with seat height, then seat depth, backrest, armrests, and tilt, so your feet sit flat and your low back stays supported.
Most people tweak one lever, sit down, and call it done. Then the lower back aches by noon. The right order matters because each adjustment builds on the last one. Set the height first, work through the rest in sequence, and you’ll get a chair that fits your body instead of one you fight all day. The setup takes about five minutes.
Start With Seat Height
Stand in front of the chair and raise the seat until the highest point sits just below your kneecap. Sit down. Your feet should rest flat on the floor, with your thighs roughly parallel to the ground and your knees level with or slightly below your hips.
If your feet dangle, the chair is too high. That pushes your shoulders up toward the desk and puts strain on your neck. Lower the seat until your soles make full contact. If the chair won’t go low enough for your feet to sit flat, you’ll need a footrest rather than a higher desk.
Set the Seat Depth and Backrest
Seat depth controls how much of your thigh the chair supports. Slide the seat pan forward or back until you can fit two to three finger widths between the back of your knee and the front edge of the seat. If the edge presses into the backs of your knees, the pan is too long, and that pressure can cut off circulation.
Next, adjust the backrest height so the lumbar support fits the natural curve of your lower back. It should press gently into the small of your back when you sit upright. If the curve sits too high or too low, you lose the support and your back muscles take over. Then set the backrest angle to a comfortable upright position, usually somewhere in the 90 to 110 degree range. A slight recline with the seat tilt can ease pressure on the spine, and a rocking tension adjustment lets you move while you work.
Position the Armrests and Check the Whole Setup
Armrests should barely touch the undersides of your elbows, with your shoulders relaxed and your elbows bent near 90 degrees. Rest your arms naturally and adjust the height until your forearms sit supported without lifting your shoulders. Armrests that force your shoulders upward or keep you from getting close to the keyboard are worse than none. If they won’t go low enough, guidance from workplace safety groups recommends removing them entirely.
Pull yourself to the desk so your forearms rest comfortably on the surface while your back stays against the chair. Then take a moment to recheck everything while actually typing. The final position often needs small tweaks once your hands are on the keyboard. If your current chair lacks the adjustments to make this work, see our tested picks for the best work from home office chair.
| Adjustment | Correct Position | Most Common Mistake |
|---|---|---|
| Seat height | Feet flat, thighs parallel, knees at or below hips | Chair set too high, so feet dangle |
| Seat depth | 2–3 finger widths behind the knee | Seat edge pressing into the back of the knees |
| Lumbar support | Fits the curve of the lower back | Support too high, too low, or not touching |
| Backrest angle | 90–110 degrees upright | Slouching or reclining too far |
| Armrests | Elbows near 90 degrees, shoulders relaxed | Armrests lifting the shoulders upward |
What to Avoid After Setup
Stopping after the chair alone is the biggest mistake. Your desk height and monitor position matter just as much. If the desk sits too high, you’ll shrug your shoulders no matter how the chair is set. If the monitor sits too low, your neck bends forward and undoes the back support you just dialed in.
These instructions are general ergonomic guidance for office and computer chairs, not a fix for every design. Ergonomic guidance from the Canadian Centre for Occupational Health and Safety, WorkSafe Queensland, and the University of Guelph agree on the body positions, even though they come from different countries. A chair without these adjustments may simply be the wrong tool, and that’s when a different chair or accessories make sense.
FAQs
How do I know if my chair is too high?
If your feet can’t rest flat on the floor or your thighs slope downward toward your knees, the seat is too high. Lower it until your soles make full contact with the ground and your thighs stay parallel to the floor. Dangling feet force your shoulders up and strain your lower back.
Should armrests touch the desk?
No. Armrests should support your elbows, not reach for the desk. Set them so they barely touch the undersides of your elbows with your shoulders relaxed. If the armrests stop you from pulling close to your keyboard, removing them gives you more room to work.
What angle should my chair back be set at?
Set the backrest between 90 and 110 degrees for most computer work. A slight recline reduces pressure on the spine, but leaning back too far makes you reach forward to the keyboard. Adjust the tilt so your back stays against the chair while your hands rest on the desk.
References & Sources
- Canadian Centre for Occupational Health and Safety. “Office Ergonomics: Adjusting Your Chair.” Details seat height, leg clearance, lumbar support, and armrest positioning.
- WorkSafe Queensland. “Selecting and Adjusting Your Chair.” Guides seat depth, backrest tilt, and armrest setup for computer work.
- University of Guelph. “Ergonomic Guidelines.” Outlines the adjustment order and footrest guidance.