Almost every desk sold is built at the same height, somewhere between 73 and 75 cm. Almost no two people are the same height. The gap between those two facts is where a large share of neck and shoulder pain comes from.
Enter your standing height and the calculator works out where your seat, your desk, and the top of your screen should be. Add the heel thickness of the shoes you actually wear at the desk, since that is part of the measurement whether you count it or not.
| Measurement | Target |
|---|---|
| Seat height, floor to top of the cushionFeet flat, knees at roughly a right angle. If the chair will not go this low, a footrest does the same job. | |
| Desk height, floor to work surfaceForearms level, shoulders down. Most fixed desks are built at 73 to 75 cm, which is why so many people sit too low for their desk rather than too high. | |
| Top of the screenTop edge at or just below eye level, an arm's length away. | |
| Standing desk heightSame forearm rule, standing. | |
| Clearance needed under the deskSpace above the thighs. Below this the drawer unit is what stops you sitting properly. |
These come from body-segment ratios published by Drillis, R. and Contini, R., Body Segment Parameters, Report 1166-03, Office of Vocational Rehabilitation, New York University, 1966: popliteal height 0.250 of standing height, seated elbow rest 0.185, seated eye height 0.450, standing elbow height 0.630, thigh clearance 0.128. They are population proportions, so they place you within a couple of centimetres, not exactly. Set the chair from the numbers, then judge by your forearms and your feet, which are the two things that actually have to be right.
The order to do this in
Chair first, then desk, then screen. Set the seat so your feet are flat and your knees sit at about a right angle. Then look at the desk: if it is higher than your forearms want, raise the chair to meet it and put something solid under your feet. Almost everyone does this backwards, dropping the chair to reach the desk, which lifts the shoulders towards the ears for eight hours a day.
A footrest can be a ream of paper or a shoebox. It does not need to be bought.
Screen height
The top edge of the screen at or slightly below eye level, roughly an arm length away. Laptop users cannot have this and a decent keyboard position at the same time, which is the whole argument for a stand and a separate keyboard. A stack of books does the same work.
If you wear varifocals, sit the screen lower than the figure here. You will otherwise tip your head back all day to find the reading segment, and that tends to produce exactly the neck pain the setup was meant to prevent.
How accurate is this
The ratios are population averages, so they will put you within a couple of centimetres rather than exactly right. Long-legged and short-legged people at the same standing height need different seats. Use the numbers as the starting position, then judge by the two things that actually have to be true: forearms roughly level with the desk, feet flat and supported.
The part no height fixes
A well measured desk that you sit at motionless for four hours is still a problem. Changing position beats holding a good one. Standing for part of the day helps, though not because standing is virtuous: it helps because it forces a change.