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How to adjust an office chair, step by step

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In short

Start with seat height so your forearms are roughly horizontal at the keyboard, then add a footrest if your feet do not rest flat. Next set seat depth so there is a gap of a few fingers behind your knees, then the back angle and tilt tension, then lumbar height so it fills the curve of your lower back, and finally the armrests so they support your arms without lifting your shoulders.

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Rear view of a man spinning on a swivel chair in a minimalist interior setting
Photo: Vitaly Gariev on Pexels

Most office chairs are used exactly as they came out of the box, which is a waste of all those levers. Ten minutes setting up a chair properly makes it fit you, and the order matters, because each setting affects the next. This guide follows the order used in the HSE display screen equipment guidance: desk and seat height first, then the parts that support your back and arms. It also explains how the common controls usually work, though every chair is different, so keep your manual to hand.

Before you start

Sit as you normally would for work, in your usual shoes. Clear the area under the desk so you can pull the chair in. If your desk height adjusts, as on a sit-stand desk, set the desk after the chair so that both meet at your elbow height. Have a look under the seat and identify each lever or knob; most chairs label them with small icons.

forearm roughly levelthigh roughly levelfeet flat123456
  1. 1Seat height (gas lift)
  2. 2Seat depth slide
  3. 3Lumbar height and depth
  4. 4Back angle and tilt tension
  5. 5Armrest height
  6. 6Headrest
The adjustment points of a task chair, with a seated outline: feet flat, thighs and forearms roughly horizontal.

Step 1: seat height and feet

Seat height comes first because everything else depends on it. The HSE guidance suggests your forearms should be roughly horizontal with your hands on the keyboard, and your elbows roughly level with the desk top or keys. Your feet should rest flat on the floor or a footrest.

  1. 1

    Stand in front of the chair and lift the seat-height lever, usually on the right under the seat.

  2. 2

    Sit down with the lever lifted to lower the seat, or take your weight off to let it rise.

  3. 3

    Release when your forearms are roughly horizontal at the keyboard.

  4. 4

    If your feet now dangle or only your toes touch, add a footrest rather than lowering the seat.

  5. 5

    If your thighs slope steeply up, the seat is too low for the desk; raise it or lower the desk.

Step 2: seat depth

Seat depth decides how much of your thighs the seat supports. Sit right back so your lower back touches the backrest. There should be a gap of roughly two to four fingers between the front edge of the seat and the back of your knees. If the edge presses behind your knees, slide the seat back; if there is a large gap, slide it forward.

The seat-depth control is usually a lever on the side of the seat or a second lever under the front. Pull it, slide the seat with your body weight and let go to lock. If your chair has no seat depth adjustment, a lumbar cushion can bring you forward on a seat that is too deep.

Step 3: back angle, tilt and tension

Most task chairs let the back move as you lean. For typing, many people prefer the back close to upright or slightly reclined. Use the tilt lock to hold it there, or leave it free and set the tension so the back follows you without pushing you forward or letting you fall back.

Tension is usually a large knob under the front of the seat: turn it one way for firmer, the other for lighter. Weight-activated chairs set this for you. Our tilt mechanisms article explains synchro, knee-tilt and forward tilt.

Step 4: lumbar support

The lumbar support should sit in the inward curve of your lower back, usually around belt height. Move it up or down until it fills that curve without pushing you forward. If it also adjusts in depth, start shallow and increase until you feel supported. On chairs with a height-adjustable backrest, moving the whole back moves the lumbar with it. See our lumbar support guide for the details on each type.

Step 5: armrests, headrest and a final check

Set the armrests last. They should support your forearms lightly with your shoulders relaxed, at or just below desk height, so they do not stop you pulling in close. If they collide with the desk, lower them, slide them back or flip them up. Our armrests explained article covers 2D, 3D and 4D arms.

A headrest is for leaning back, not for typing; set it so it meets the back of your head when you recline. Finally, sit for a few minutes, then recheck seat height and lumbar. The HSE checklist also covers screen position and breaks, so look at the whole workstation, not just the chair.

Note:If a lever is stiff or a gas lift moves on its own, stop and check the chair before carrying on. A faulty gas lift should be replaced, not forced.

See chairs with full adjustment →

Frequently asked questions

How does office chair height adjustment work? A gas lift cylinder holds pressurised gas. The lever opens a valve; your weight pushes the seat down, and the gas pushes it up when you stand.

How do I adjust seat tilt? Look for a lever that locks the tilt and a knob that sets tension. Some chairs also have a seat-angle or forward-tilt lever.

What if my desk is too high? Raise the chair until your forearms are level and add a footrest. If you have a sit-stand desk, lower it instead.

How often should I readjust? Whenever someone else uses the chair, or if you change shoes, desk or screen setup.

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