Office seating should be comfortable, appropriate to the undertaken task, and easy for the operator to adjust. 

In general, seats: 

  • should be adjustable to the task and be easily adjusted from the seated position

  • should be height-adjustable, preferably utilising a gas lift for ease of adjustment

  • should have a curved front edge to minimise pressure on the underside of the thighs

  • should have a supportive backrest that is adjustable in height, angle and depth

  • should be covered by cloth or some other type of material that breathes (this also applies to the backrest), and

  • should have a five-star base for stability.  

Armrests are optional: they help decrease the forces on the shoulders and back but can limit access to the desk. Some employees prefer to rest their forearms on the work surface. If provided, the armrests should be height adjustable. 

In general, chairs are designed to fit 90 to 95% of the adult population. People outside this range, tall or short, may need seating that is tailored to their needs. 

 

Alternative seating 

Some forms of alternative seating are designed to enable people to sit with the hips at an angle that is believed to reduce pressure on the lower back. It is difficult to say whether this seating is better or worse than conventional adjustable office chairs. This seating is usually chosen by personal preference, for example, by someone with low back pain. 

Examples include the 'kneeling' chair, the 'sit-stand chair or 'saddle' chair, and the 'physio' or 'sit' ball. 

 

How to set the correct seat height of an adjustable office chair 

The chair height should be set so that the thighs are approximately horizontal and the feet rest comfortably on the floor. 

If the chair height is correctly set, but the desk is too high, either lower the desk height or raise the chair's height and use a footrest to make up the height difference of the feet above the ground. 

Combine chair and desk adjustments to position the work at elbow height. Where writing and keying tasks are performed, it may be necessary for the chair height to be adjusted slightly between these two tasks (that is, raised for keying and lowered for writing). 

If the thighs are wedged between the chair and the undersurface of the desk, or the knees bump into the front of the desk, then either the desk is too low, the chair is too high, the desktop or keyboard is too thick, or the user is too tall for the chair and desk. An ergonomist should be consulted for advice in this situation. 

 

How to decide if you need a foot-rest 

This will depend upon whether your desk is at the required height once you have adjusted your chair to suit your needs. If the desk is too high and cannot be lowered, raise the height of the chair and use a footrest to raise the height of the floor by the same amount. Footrests should have height and angle adjustability and be large enough to permit some movement while supporting the feet. A footrest should not be so big that it clashes with the chair base. 

 

How to decide if you need armrests 

Armrests are suitable for people who perform various tasks at a workstation, frequently move to and from their chair, or sit back in their chair to talk to visitors. Armrests are less suitable for keying work, as the elbows may rest on the armrests and cause the shoulders to be raised into an unnatural posture. Armrest designs should not limit forward chair movement by contacting the desk. 

 

Purchasing chairs 

Before purchasing new chairs, it is important to assess the use of the chairs and the design features needed. Safe Work Australia's Ergonomic Principles and Checklists for the Selection of Office Furniture and Equipment  should be used for guidance for selection. 

Relevant Australian Standards on office furniture, such as AS/NZS 4442:2018 Office desks, office workstations and tables intended to be used as office desks - Mechanical, dimensional and general requirements and test methods may also provide useful guidance. It is the responsibility of suppliers to advise if chairs meet the Australian Furniture Research and Development Institute (AFRDI) Standards. 

Trial use of chairs in the office is advisable before purchase. 

 

Key steps to ensure comfort 

These are key steps to ensure employees get maximum comfort from their office chair: 

  • Sit in the chair and push your hips as far back as they can go in the chair.  

  • Adjust the seat height so your feet are flat on the floor and your knees are equal to or slightly lower than your hips. A footrest may be required if your feet are not flat on the floor. 

  • Adjust your chair height or work desk (if possible) so that the work surface is approximately at finger length below the height of the elbow when seated. 

  • Adjust the backrest angle, so you can sit upright while keying. Ensure your upper and lower back are supported. Adjust backrest regularly to enable you to make frequent position changes.  

  • Adjust the backrest height to fit into the small (curvature) of your back to provide support to your back .

  • Ensure you can get close to your work desk without impediment and that armrests are not in the way. Armrests are not recommended for long periods of keying unless they are well out of the way of the desk. When using armrests, ensure you adjust them so that your shoulders are relaxed.