Quick rule: Proper chair height is not the same for everyone. Your chair is at a suitable height when your feet are supported, your legs are comfortable, and you can work at your desk without raising your shoulders or reaching awkwardly.
The goal is not to force your body into a perfect 90-degree position. It is to make your chair, desk, and body work together.
For a Quick Chair height calculation, use this tool
How to Know if Chair Is Too High or Too Low
| Chair position | What you may notice | What to do |
| Too high | Feet don’t reach the floor, pressure behind knees, tendency to slide forward | Lower the chair if possible; otherwise consider a footrest |
| Too low | Knees sit high and the desk may feel too high relative to your arms | Raise the chair if your feet remain supported |
| Suitable | Feet supported, legs comfortable, shoulders relaxed while working | Recheck the entire workstation |
A chair that is too high can leave your feet unsupported or encourage you to move forward, reducing back support. OSHA recommends a footrest when lowering the chair would create another workstation-height problem. (OSHA)
Proper Chair Height: Quick Check & Solutions
| If you notice… | What it likely means | Quick solution |
| Feet don’t touch the floor | Chair is too high | Lower the chair or use a stable footrest |
| Feet are flat but knees feel cramped | Chair may be too low or seat depth may be wrong | Raise the chair slightly and check seat depth |
| Pressure behind your knees | Seat may be too high or too deep | Lower the chair and check seat depth |
| Knees are much higher than hips | Chair may be too low | Raise the chair if your feet remain supported |
| Shoulders rise when typing | Desk may be too high for your chair | Raise the chair if possible; use a footrest if needed |
| You slide forward to reach the floor | Chair is likely too high | Lower the chair or add foot support |
| Feet, legs and shoulders feel comfortable | Chair height is likely appropriate | Keep the setting and reassess your full workstation |
| Chair feels right but your arms don’t | Desk/keyboard height may be the problem | Adjust the desk, keyboard or chair relationship |
How to Set Your Chair to the Proper Height
You can adjust most office chairs in a few steps.
1. Start with your feet
Sit normally and place both feet flat on the floor.
Your feet should not dangle, and you should not have to sit forward just to reach the floor. If your chair needs to stay higher because of your desk, a stable footrest can provide the necessary support. (CCOHS)
2. Check your knees and thighs
Your knees should be comfortably bent, with your thighs supported by the seat.
A 90-degree knee angle is a useful reference point, but it does not need to be exact. OSHA’s workstation guidance allows the thighs to be approximately parallel to the floor, while noting that the knees may be slightly higher in some seating positions. (OSHA)
3. Check the space behind your knees
The front edge of the seat must not press into the back of your knees.
CCOHS recommends roughly 5 cm (2 inches) of clearance between the seat edge and the lower legs as a practical adjustment check. (CCOHS)
4. Check your working position
Now place your hands on the keyboard or desk.
Your shoulders should remain relaxed rather than creeping upward, and your elbows should stay close to your body. Your forearms should be approximately level with the work surface. (OSHA)
5. Recheck after sitting normally
Don’t judge your chair after sitting rigidly for a few seconds. Sit as you normally work and see whether your feet, legs, back, and arms remain supported.
That’s the real test of proper chair height.
How Chair Height Should Relate to Your Desk
Your chair and desk need to be adjusted as a pair.
If you lower your chair enough to keep your feet flat but the desk is then too high for comfortable typing, your shoulders may have to rise, or your arms may sit awkwardly. On the other hand, raising the chair to reach a high desk can leave your feet unsupported. (CCOHS)
A better approach is:
Set the chair for your lower body → check your desk and elbows → add a footrest if necessary.
If your desk is fixed and too high, raising the chair and supporting your feet with a footrest can be more practical than sacrificing either your working position or foot support. (CCOHS)
This is why there is no single “perfect” chair height that works for everyone.
What If Your Feet Don’t Touch the Floor?
If your feet cannot reach the floor at your preferred working height, don’t simply let them hang.
First, check whether you can lower the chair without making your desk position uncomfortable. If you cannot, use a stable footrest that supports both feet. Mayo Clinic also recommends a footrest when the chair must be high enough to accommodate the desk. (Mayo Clinic)
This is particularly important for shorter users, but it can happen to anyone depending on the chair and desk combination.
Also check the seat depth. A seat that is too deep can press behind the knees or prevent shorter users from sitting fully against the backrest. OSHA recommends a seat pan that supports the thighs without contacting the back of the knees. (OSHA)
Other Chair Adjustments That Affect Proper Height
- Seat depth: You need thigh support without pressure behind the knees.
- Armrests: They should support the arms without forcing your shoulders upward or preventing you from getting close to the desk.
- Backrest: It should support your lower back without forcing you into an awkward position. (CCOHS)
If adjusting the chair seems to fix one problem but creates another, the issue may be the relationship between your chair and workstation, not the chair height itself.
Common Proper Chair Height Mistakes
Avoid these common errors:
- Choosing chair height only by your body height. Leg length and workstation dimensions also matter.
- Treating 90 degrees as mandatory. It is a useful reference, not a measurement you need to maintain perfectly.
- Ignoring dangling feet. Use a stable footrest when necessary.
- Lowering the chair to solve every problem. A high desk may require a different solution.
- Ignoring seat depth. A poorly sized seat can create pressure behind the knees even when its height is appropriate.
- Raising the chair and shrugging your shoulders. If your arms cannot comfortably reach the work surface, reassess the desk and keyboard position.
Proper Chair Height Checklist
Your chair height is likely well adjusted if:
- Your feet are fully supported.
- Your knees are comfortably bent.
- Your thighs are supported without excessive pressure.
- The seat edge does not press behind your knees.
- Your hips and knees feel comfortable.
- Your shoulders stay relaxed while working.
- Your elbows can reach the keyboard without shrugging.
- You can sit back against the chair while remaining close enough to your desk.
If one of these checks fails, adjust the chair and reassess the workstation rather than chasing a single measurement.
FAQs
What is the proper chair height?
The proper chair height is one that supports your feet and legs while allowing a comfortable working position. Your feet should rest on the floor or a stable footrest, your knees should be comfortably bent, and the chair should work with your desk rather than forcing awkward arm or shoulder positions. (OSHA)
Should your feet touch the floor when sitting?
Ideally, yes. If your chair must remain higher because of the desk, use a stable footrest so your feet remain supported. (Mayo Clinic)
Should your knees be at 90 degrees?
Not necessarily. A roughly 90-degree angle can be a useful reference, but ergonomic guidance does not require an exact angle for every person or situation. (OSHA)
How do I know if my office chair is too high?
Signs can include unsupported or dangling feet, pressure behind the knees, or needing to move forward in the seat to reach the floor. (OSHA)
How do I know if my office chair is too low?
Your knees may sit noticeably high, and your desk may feel too high relative to your elbows and hands. If raising the chair improves your working position but leaves your feet unsupported, consider a footrest.
Should chair height match desk height?
Not as an exact measurement. The important thing is that your chair and desk allow supported feet, comfortable legs and relaxed shoulders and arms while you work. (CCOHS)
What should I do if my feet don’t touch the floor?
Lower the chair if doing so still allows a comfortable working position. If the chair needs to stay higher, use a stable footrest rather than leaving your feet unsupported. (CCOHS)
Does chair height affect posture?
It can. A poorly adjusted chair may contribute to unsupported feet or awkward positions, while a properly adjusted workstation can help reduce awkward postures. (OSHA)
Does seat depth matter?
Yes. A seat that is too deep can press against the backs of the knees or prevent shorter users from sitting comfortably against the backrest. (OSHA)
What is the proper chair height for a short person?
There is no single height based solely on being short. The chair should allow supported feet and a comfortable working position. If the chair must remain high for the desk, a footrest can help.
The Bottom Line
Proper chair height is a position, not a number. Start by supporting your feet, check your knees and thighs, make sure the seat is not pressing behind your knees, and then adjust your desk and keyboard so your shoulders and arms can stay relaxed.
If you have to compromise one part of the setup to fix another, don’t keep adjusting the chair blindly. Look at the chair, desk, and foot support as one system.
And remember: an ergonomic setup is not about sitting perfectly still all day. Change positions regularly and take movement breaks throughout your workday. (CCOHS)
