Office Chair Setup: Seat Height, Depth and Back Support
Desk checklist
| Setting | Aim for | Quick check |
|---|---|---|
| Seat Height | Your feet should be flat on the floor or a footrest, with your thighs roughly parallel to the floor. Your knees should be at about the same height as your hips, or slightly lower. | Are your feet flat on the floor with your knees at or slightly below hip level? |
| Seat Depth | Sit with your back fully against the backrest. There should be a small gap, about two to three fingers wide, between the front edge of the seat and the back of your knees. | Does the seat edge press into the back of your calves? If so, the seat is too deep. |
| Backrest Support | Adjust the backrest so it supports the natural curve of your lower back. The angle should be slightly reclined from vertical to reduce pressure on your spine. | Does the curve of the backrest fit comfortably into the small of your back? |
| Lumbar Support | If your chair has adjustable lumbar support, position it to fit the curve of your lower back. It should provide gentle support without pushing your spine forward or feeling intrusive. | Do you feel even, light pressure in your lower back, helping you maintain a natural curve? |
| Armrest Height | Adjust armrests so your shoulders are relaxed and your elbows are bent at a comfortable, open angle. | Are your shoulders relaxed and not hunched up towards your ears? Your forearms should be lightly supported. |
| Swivel and Casters | The chair should allow you to turn and move easily to reach different parts of your desk without twisting your back or overreaching. | Can you turn and roll smoothly to access items without straining? |
Adjusting your office chair is a key step for creating a more comfortable workstation. A well adjusted chair supports your body’s natural posture, which can help reduce strain on your back, neck, and shoulders during the workday.
The goal is to set the chair up to fit your body, not to force your body to fit the chair. This involves adjusting several parts of the chair to match your specific needs.
Key Chair Adjustments for Your Body
Start with seat height. Your feet should be flat on the floor or a footrest, with your thighs about parallel to the floor. Your knees should be at the same height as your hips, or a little lower. Next, check the seat depth. When you sit with your back against the backrest, there should be a small gap of about two to three fingers between the front of the seat and the back of your knees. If the seat edge presses into your calves, it is too deep.
Adjust the backrest to support the natural curve of your lower back. It should be slightly reclined from a fully vertical position to reduce pressure on your spine. If you have adjustable lumbar support, position it to fit this curve, providing gentle support without pushing you forward. Finally, set your armrests so your shoulders are relaxed, not hunched. Your elbows should be bent at a comfortable, open angle with your forearms lightly supported.
Common Mistakes and Simple Fixes
A frequent mistake is setting the chair too high, leaving feet dangling and putting pressure on the thighs. Another is sitting on the edge of the seat, which means you get no support from the backrest. Avoid positioning armrests too high, which hunches the shoulders, or locking the backrest in a perfectly upright position, which can increase spinal pressure.
If your chair lacks good lumbar support, you can use a firm cushion or a rolled up towel to support the small of your back. If your feet don’t reach the floor when the chair is at the right height for your desk, use a stable box, a stack of sturdy books, or a footrest. For non adjustable armrests that are the wrong height or prevent you from getting close to your desk, you might consider removing them.
Remember that a well adjusted chair is only one part of a comfortable workstation and does not replace the need for regular movement and breaks from sitting. These adjustments may not resolve issues caused by desk height or monitor position.
Common mistakes
- Setting the chair too high, causing feet to dangle and pressure on the back of the thighs.
- Sitting on the front edge of the seat, away from the backrest and its support.
- Positioning armrests too high, which hunches the shoulders, or too low, which causes leaning.
- Ignoring the seat depth adjustment, leading to poor back support or pressure behind the knees.
- Locking the backrest in a perfectly upright position, which can increase pressure on the spine.
Low-cost fixes
- Use a firm cushion or a rolled-up towel to provide extra lumbar support if your chair lacks an adjustable feature.
- Use a stable box, a stack of sturdy books, or a dedicated footrest if your feet do not comfortably reach the floor.
- If non-adjustable armrests prevent you from getting close to your desk or are at the wrong height, consider removing them.
What it will not do
- A well-adjusted chair does not replace the need for regular movement and breaks from sitting.
- Chair adjustments alone may not resolve discomfort caused by other factors like desk height or monitor position.
- This guidance is for standard adjustable office chairs and may not apply to alternative seating like kneeling chairs or balance balls.
Quick questions
What is the proper chair height for a desk?
Adjust your chair so your feet are flat on the floor or a footrest. Your thighs should be roughly parallel to the floor, with your knees at about the same height as your hips or slightly lower.
How far back should I sit in my office chair?
You should sit with your back fully against the backrest. There should be a small gap, about two to three fingers wide, between the front edge of the seat and the back of your knees.
What can I do if my chair has no lower back support?
If your chair lacks an adjustable lumbar feature, you can use a firm cushion or a rolled up towel to provide extra support for the curve of your lower back.
When to see a doctor or physio
If you have persistent or worsening pain, numbness, or tingling in your back, neck, or legs, it may be time to see a doctor or physical therapist. You should also seek advice if you cannot get comfortable despite making adjustments or if discomfort interferes with your work.
- You experience persistent or worsening pain, numbness, or tingling in your back, neck, hips, or legs.
- You cannot get comfortable in your chair despite trying all available adjustments.
- Your discomfort interferes with your ability to perform your work tasks.
- You have a pre-existing medical condition that affects your ability to sit comfortably for work.
How this page was put together: general guidance consistent with public workstation and movement-break resources from OSHA, CDC/NIOSH and the NHS, and with standard exercise handouts. It was drafted with AI assistance, checked in a separate review pass and edited under our editorial policy. It is not medical advice and no clinician reviewed it. Last checked October 2026.