How do I sit at a desk without ending up sore?

The order to adjust things in — chair, then desk, then screen, then keyboard — and why sitting still is the real problem.

Difficulty: beginner
Time: 30 min
Read: 2 min
Safety: caution

Short answer

Set the chair height first so your feet are flat and elbows around 90 degrees, then bring the screen to eye level. And whatever the setup, get up every half hour — the best position held for eight hours is still bad.

There is a correct order for this, and doing it in the wrong order means readjusting everything. Chair first, because everything else is measured relative to where your body ends up.

Safety

General setup guidance for everyday comfort. Persistent pain, numbness or tingling in the hands or arms should be assessed properly rather than adjusted around — those can indicate something a desk change will not fix.

Step by step

Set the chair height first.Feet flat on the floor, thighs roughly parallel to the ground, knees at about 90 degrees. If the chair cannot go low enough, get a footrest — a stack of books works.
Adjust the backrest to support your lower back.The curve of the backrest should sit in the curve of your lower back. A rolled towel works if the chair has no lumbar support.
Set the desk height relative to your elbows.Elbows at roughly 90 degrees with shoulders relaxed when your hands are on the keyboard. Shoulders creeping up means the desk is too high.
Put the screen at eye level.The top of the screen roughly level with your eyes, about an arm's length away. Looking down at a laptop for hours is the single biggest cause of desk-related neck pain.
Use a separate keyboard and mouse with a laptop.A laptop cannot have both the screen and the keyboard in the right place at once. Raise the laptop and add a keyboard — this is the highest-value change most home setups can make.
Keep the mouse close.Beside the keyboard, at the same height. Reaching forward or out to the side for hours causes shoulder problems.
Sort out the lighting.Avoid a window directly behind or in front of the screen. Glare causes squinting and leaning forward, which undoes the rest of the setup.
Get up every 30 minutes.The most important item here. No position is good for eight hours. Standing, walking to the kettle, or a brief stretch — regularly.

Tips

A laptop stand and a separate keyboard cost very little and fix the majority of home-working discomfort.
A standing desk is not automatically better — standing still for eight hours has its own problems. Alternating is what helps.
If your employer provides a workstation assessment, use it. They are usually obliged to, and it costs you nothing.

Common mistakes

Working on a laptop on a table for hours — The screen is far too low, which loads the neck continuously. A stand and a separate keyboard fixes it for very little money.
Setting the desk before the chair — Everything is measured relative to your seated position. Getting the chair right first avoids adjusting everything twice.

Questions people ask

What is the most important part of a desk setup?

Screen height, and then getting up regularly. A screen that is too low loads the neck continuously, and no position is good for eight hours.

Do I need an expensive chair?

Not necessarily. Adjustability matters more than price — height, backrest and lumbar support. A cheap chair set up well beats an expensive one set up badly.