Office Ergonomics: Desk, Chair and Screen Set-up

Why is office ergonomics set up in order?

Office ergonomics is not a furniture purchase but an adjustment made to suit the person. Annex 1 of the Regulation on Health and Safety Measures in Work with Display Screen Equipment lists the minimum requirements: a chair with adjustable seat height, a backrest adjustable forwards and backwards and up and down, a footrest if requested, a keyboard separate from the screen and movable, and a screen at eye level that can swivel. The regulation does not give measurements; these are given by the General Directorate of OHS's Guide to OHS in Work with Display Screen Equipment and by ergonomic principles in practice.

Adjusting in the right order matters because each step depends on the previous one. If you set the screen first and then raise the chair, the screen ends up at the wrong height again. The correct order is: chair → desk → keyboard and mouse → screen. For the legal framework and obligations such as eye examinations, see our article on working with display screen equipment; this article focuses on the set-up itself.

Step 1: Ergonomic chair adjustment

Ergonomic chair adjustment is the foundation of the whole set-up:

1. Seat depth: Lean back against the backrest. There should be a few fingers' width between the backs of your knees and the front edge of the seat; the seat should not press against the backs of the knees.
2. Seat height: The guide's practical method is this: when pressing the G and H keys on the keyboard, your elbows should be bent at about 90 degrees and about 2 cm above the desk surface. The forearms are roughly parallel to the floor.
3. Feet: If your feet do not rest flat on the floor at this height, use a footrest. The regulation requires a suitable footrest to be provided on request.
4. Lumbar support: The backrest's lumbar support is adjusted up or down so that it sits in the hollow of your lower back.
5. Backrest angle: Choose an angle at which you can lean back slightly without having to reach towards the screen.
6. Armrests: They should not push your shoulders up or stop you getting close to the desk; if they do, lower or remove them.

Step 2: Desk height

If the desk height is fixed, you make the adjustment with the chair and a footrest: the chair is raised according to the elbow rule and the feet rest on the footrest. If the desk is adjustable, first set the chair for your leg length, then bring the desk to elbow height.

For desks that allow standing work, the guide gives this criterion: with the shoulders relaxed, the elbows are bent at 90 degrees and the desk height is set just below the arms. When working standing, do not keep your weight on one leg all the time, and change your posture during the day.

Also check the desk depth. The regulation requires the work surface to be large enough for the screen, keyboard and documents to be placed comfortably, and to be non-reflective. On a narrow desk the screen comes too close to the eyes and there is no room in front of the keyboard for wrist support; in this case a monitor arm frees up space by moving the screen to the back edge of the desk.

Leave enough space under the desk to move the legs freely. A computer case, archive box or bin placed under the desk forces the worker to sit sideways.

Step 3: Keyboard and mouse

Placing the mouse far from the keyboard makes the arm reach out from the shoulder and leads to shoulder fatigue. For a worker who spends most of their time using the mouse, a mouse mat with wrist support can provide comfort.

Step 4: Screen height, distance and position

The guide's rule for screen height is clear: the top edge of the monitor is at eye level. For those wearing bifocal or progressive glasses, the screen should be a little lower; otherwise the worker tilts their head back to read the screen through the lower part of the glasses.

The distance is chosen according to the size of the text on screen. The approximate values given in the guide are:

According to the example in the guide, when reading 12-point Times New Roman text in Word at 100% zoom, about 50 cm is suitable. If you lean forward to read the text, increase the zoom level rather than moving the screen closer.

There are two more rules for position. The screen should be directly in front of you; you should not have to keep turning your head to the side. The desk should also be positioned so that light from the window comes from the side: if the window is behind the screen there is glare, and if it is in front of it there are reflections on the screen. The regulation also requires adjustable blinds to control daylight.

Laptop ergonomics and dual monitors

The problem with a laptop is that the screen and keyboard are attached to each other: if you raise the screen to eye level the keyboard is too high, and if you keep the keyboard at elbow height the screen is too low. The guide therefore recommends a raising stand for the screen on laptops. For prolonged use, the following set-up works:

• Put the laptop on a stand and bring the top edge of the screen to eye level.
• Connect a separate keyboard and mouse; position them according to the rules in step 3.
• If possible, use the laptop as a second screen and connect an external monitor for the main work.
• Follow the same order when working from home; the kitchen table and the sofa are for short tasks.

For dual monitors, the regulation and guide give no separate measurement; the following recommendations follow from ergonomic principles:

• If you use both screens equally, the edge where they meet should be directly in front of you and the screens should be angled slightly towards you.
• If one is the main screen, the main screen should be directly in front of you and the second next to it at the same angle.
• The top edges of the two screens should be at the same height and at about the same distance from your eyes; with screens of different sizes, equalise the height with a stand.

Common set-up mistakes

A large proportion of ergonomic problems arise not from a lack of expensive equipment but from a few simple mistakes:

• The chair is never adjusted. An adjustable chair is bought, but no one shows what the adjustment levers do. The guide requires users to know the chair's adjustments and to be trained if necessary; Art. 6 of the regulation also lists correct sitting posture among training topics.
• The screen is placed in front of or behind a window. Moving the desk is the quickest solution in an office without blinds.
• Documents are laid flat on the desk when working with paper. Constantly looking down and back to the screen increases neck movement. The regulation requires the use of an adjustable document holder to reduce eye and head movements; place the document next to the screen at the same height.
• Holding the phone between shoulder and ear. For those working on the phone all day, a headset significantly reduces the load on the neck.
• One setting at shared desks. In flexible seating arrangements, each worker should readjust the chair and screen for themselves when taking a desk; adjustable monitor arms make this easier.
• Bright screen and reflections. Finding the source of the reflection and turning the screen or changing the lighting is more effective than turning the brightness all the way up. According to the guide, dark characters on a light background are less prone to glare.

Breaks, eye examinations and risk assessment

A correct set-up does not compensate for staying still all day. Art. 7 of the regulation requires the employer, through a suitable work plan, to ensure that operators take periodic breaks or alternate with other tasks. The guide also recommends frequent breaks, resting the eyes for short periods and stretching exercises. Doing tasks such as meetings, printing or phone calls standing up is a simple method.

An eye examination is carried out before starting work with display screen equipment, at intervals set by the workplace physician and when visual difficulties occur (Art. 9). Display screen equipment risks, particularly to vision, musculoskeletal problems and mental stress, should be included in the workplace's risk assessment (Art. 5). For the workload and stress side, see our article on psychosocial risk factors.

Offices are usually in the less hazardous class; however, this does not mean that ergonomic risks are not assessed. You can see your obligations in our article on obligations of less hazardous workplaces and with the OHS obligation calculator. For workstation assessment in offices and shops, see our risk assessment service and our office and retail page.

Frequently Asked Questions

What height should the screen be?

The top edge of the screen should be at eye level; a little lower for those wearing bifocal or progressive glasses. The screen should be directly in front of you and readable without tilting your head back or turning it to the side.

How many centimetres high should the desk be?

There is no single correct value; the criterion is the person's elbow height. When working seated, the elbows should be at about 90 degrees and about 2 cm above the desk when pressing the G and H keys. If the desk is fixed, this adjustment is made with the chair and a footrest.

Is it acceptable to work all day on a laptop?

A laptop on its own is not a suitable set-up for prolonged work. By raising the screen to eye level on a stand and using a separate keyboard and mouse, you get close to a desktop set-up.

Is it mandatory for the employer to buy an ergonomic chair?

The regulation requires features, not a brand or model: a stable chair with adjustable seat height, a backrest adjustable forwards and backwards and up and down, and suitable support for the lower back. A footrest is also provided on request, and the cost of these measures cannot be passed on to the worker.