Why height matters
Most desks and chairs are built for an imagined average person. If you are taller, shorter or built differently, the default arrangement may leave your shoulders raised, your wrists bent, or your feet dangling. Small height adjustments are often the cheapest and most noticeable improvement to a workspace.
The guidelines below are general starting points, not rules. If something feels wrong after a few days, adjust it again.
Set the chair first
Always start with the chair, because it supports your body and everything else relates to it.
- Sit with your back against the backrest and your feet flat on the floor.
- Adjust the seat height until your thighs are roughly level, or tilted slightly down toward the knees.
- Check that you can slide a couple of fingers between the front edge of the seat and the back of your knees. If the seat presses into your knees, it is too deep for you; if it is much shorter than your thighs, it may feel unsupportive.
- Adjust the backrest or lumbar support so your lower back feels gently supported rather than pushed forward.
If you cannot get your feet flat without raising the chair so high that the desk becomes too low, use a footrest. A sturdy box or a stack of books can do the job temporarily, as long as it is stable and does not slide.
Armrests
Armrests, if you have them, should let your shoulders stay relaxed. Set them so your forearms rest lightly with elbows near your sides. Armrests that are too high push the shoulders up; too low and they offer no support. If they stop you from getting close enough to the desk, lower them, move them out of the way, or remove them if the chair allows it.
Match the desk to your elbows
With the chair set, let your arms hang naturally and then bend your elbows. The desk surface or keyboard tray should end up around the height of your elbows, so your forearms are about parallel to the floor, or angled slightly downward. Your shoulders should be loose, not hunched.
Common signs the desk is too high:
- Shoulders lifting toward your ears
- Wrists bending upward to reach the keys
- Tension in the neck after a short time
Signs it is too low:
- Leaning forward or slumping to reach the keyboard
- Resting your forearms on a hard edge
- A rounded upper back
If the desk height is fixed
Most standard desks are a single height. If yours is too high for you, raise the chair and use a footrest. If it is too low, you can raise the desk with sturdy risers under the legs designed for the purpose, but only if they are stable and the desk will not tip. A keyboard tray that mounts under the desk is another way to lower the keyboard relative to the surface. Be cautious with improvised stacks that could shift, particularly under heavy equipment.
Placing the keyboard slightly lower than the desktop helps many people, but be sure your knees and thighs still have room beneath it.
Standing desks and adjustable desks
If you have an adjustable desk, the same elbow rule applies when standing: your forearms should reach the keyboard at about a right angle without lifting your shoulders. Standing for hours is not automatically healthier than sitting for hours, and changing positions during the day is usually the sensible goal. Use an anti-fatigue approach that suits you, such as supportive shoes or a mat, and take a break from either position when it becomes uncomfortable.
Where the screen fits in
Once your seat and desk heights are settled, set the screen. The screen should be in front of you at a comfortable distance with the top near eye level, as covered in the article on monitor position and eye strain. If you raise your chair a lot to fit the desk, recheck the screen height afterward, because it changes where your eyes are relative to the display. Anyone who uses a laptop on a desk faces a related problem, since the keyboard and screen are bound together.
Related equipment can also affect height. Computer peripherals such as a thick keyboard or wrist rest raise your hands, and a desk setup with multiple monitors might require different riser heights for each display. A desktop or laptop choice also changes what you can adjust on a desk, so consider that when planning.
Check your posture occasionally
Once you have made adjustments, spend a few minutes checking:
- Feet supported
- Thighs roughly level
- Lower back supported
- Elbows near your sides, at a comfortable angle
- Shoulders relaxed
- Wrists in a fairly straight line with forearms
Then work as usual for a few days. A setup that feels strange at first can settle in, but pain or numbness is not something to push through. If discomfort continues or you have pain that does not ease, speak with a doctor, physical therapist or ergonomics professional, who can look at your body and your workspace together.
When to replace instead of adjust
Sometimes the furniture simply does not fit. A chair with no height adjustment, a very deep seat for a short person, or a desk with obstacles under it may justify replacing the item. Before buying anything, try the adjustments here, and borrow or sit in the chair first if you can. Consider repairability and whether a used or refurbished item would work, since chairs and desks are often long-lived.