Adjusting the correct seat height – how to do it in 3 steps

You’ve reached the correct seat height when your feet are flat on the floor and your knees form a 90-degree angle or slightly more. A good rule of thumb is: slightly too high is better than too low, because a seat that is too low puts more strain on the knees than necessary. The ergonomics experts at hjh-office.co.uk recommend following a set order so that every part of your body is properly aligned in the end.

Step 1: Legs & feet

Stand in front of your chair, adjust the seat height so it is roughly level with your knees, then sit down. Your feet should rest completely flat on the floor without you having to stretch or balance on your toes. Check the angle at the back of your knees: 90 degrees is the minimum, and a slightly wider angle of 95 to 100 degrees is usually even more comfortable and puts less strain on your joints.

Step 2: Legroom & thighs

Now for the part many people overlook: the front edge of the seat. Slide two to three fingers between the back of your knee and the edge of the seat cushion. If that fits comfortably, you have enough legroom. If the edge presses noticeably into the back of your knee, you’re either sitting too low or the seat depth isn’t adjusted properly – both can cause an uncomfortable pulling sensation in the thighs over time and may even affect circulation.

Step 3: Matching it to desk height

Only once the seat height and legroom are right should you look at the desk – not the other way around. Rest your forearms loosely on the desktop: here too, there should be an angle of around 90 degrees at the elbow, while your shoulders hang down in a relaxed position rather than being raised. If your desk is not height-adjustable and the seat height doesn’t match, it’s better to leave the chair correctly adjusted and find a solution for the desk instead of compromising on seat height.

Practical tip from hjh-office.co.uk: If you’re on the shorter side and your desk cannot be set low enough, use a height-adjustable footrest instead of raising the seat height at the expense of your legs. This keeps both your knee and elbow angles correct, regardless of desk height. If you have a height-adjustable desk, it’s easier: first adjust your chair for the best sitting position, then adjust the desk height to suit your arm position – not the other way around.