The Four Chair Adjustments Worth Making

A task chair with eight adjustment points is usually sold on the number. In practice four adjustments do nearly all the work, and getting those right matters far more than how many others exist. Set them in this order — each one changes the next.

1. Seat height, set from the floor

Sit back in the chair with your feet flat on the floor. Adjust the height until your thighs are roughly horizontal and your knees are level with, or very slightly below, your hips.

The reference point is the floor, not the desk. People routinely raise the chair to reach a desk that is too tall, which lifts the feet and puts the whole body’s weight on the back of the thighs. If your feet do not reach the floor once the seat is at the right height, you need a footrest. This is not a compromise — it is the correct solution.

2. Backrest height, set to your lower back

The lumbar curve of the backrest — the part that pushes forward — should sit in the hollow of your lower back, roughly at belt height. Too low and it pushes on your pelvis; too high and it pushes between your shoulder blades and makes you slump underneath it.

On chairs where the whole backrest moves, raise or lower it until the fullest part of the curve meets the fullest part of your inward curve. On chairs with a separate lumbar pad, move the pad rather than the backrest.

How much support

Some chairs let you set lumbar depth as well as height. Firm enough to feel is right; firm enough to arch you forward is too much. If you notice it after twenty minutes, back it off.

3. Seat depth

The least used adjustment and often the most useful. With your back against the backrest, there should be roughly two to three fingers’ width between the front edge of the seat and the back of your knees.

A seat too deep means you either sit forward and lose the backrest entirely, or sit back and have the seat edge pressing behind your knees. Either way the backrest stops doing its job. A seat too shallow gives your thighs no support.

If your chair has a sliding seat pan, use it. If it does not and the seat is too deep for you, a firm cushion behind your lower back is a workable substitute.

4. Armrest height

Set so your shoulders are relaxed and your forearms are roughly parallel to the floor when your hands are on the keyboard. The armrest supports the weight of the arm; it is not something to lean on heavily.

Armrests that are too high push your shoulders up and cause neck tension. Too low and you will lean to one side to reach them, which is worse than no armrests at all. If they cannot go low enough to be right, and they can be removed, remove them.

Also check they go low enough to slide under your desk. Armrests that collide with the desk edge stop you sitting close, which undoes the desk depth work.

The two settings people leave wrong

Tilt tension

The knob under the seat, usually stiff, that sets how hard you have to push to recline. Out of the box it is often set for someone much heavier or much lighter than you. Set it so you can recline with gentle pressure and the chair supports you at the point you stop — not so tight that it never moves, which is how most chairs are used.

Tilt lock

Leave it unlocked for normal work. Movement through the day is better for you than a fixed position, however good that position is. Lock it only for tasks needing a fixed posture.

Once it is set

Re-check after a week. The settings that feel right in a showroom often need a small adjustment once you have worked a full day in the chair. And re-check if you change desk, keyboard or shoes — heel height changes seat height.

What no adjustment fixes

Sitting still. The best-adjusted chair in the world still wants you to get up every half hour or so. A stackable guest chair for a second working position, or simply standing for calls, does more than any lever.

Our Office Seating listings state which adjustments each model has, so you can check for seat depth adjustment before ordering rather than after.