How to measure yourself for an office chair before you buy one

In our South Michigan Avenue showroom people sit in a chair before they buy it, and within thirty seconds they know whether it suits them. Buying online removes that, and the substitute is not reviews — it is four measurements against four specifications.

Take them once, write them down, and most chairs eliminate themselves before you read a single description.

The four measurements

1. Desk height

Floor to the top of the work surface. Most fixed desks are between 28 and 30 inches, which is a standard set for a fairly tall person. This is the anchor for everything else, because the chair has to bring you to the desk.

2. Lower leg length

Sit on a firm chair with your feet flat. Measure from the floor to the back of your knee. This is the seat height you need — feet flat on the floor, thighs roughly parallel to it. For most adults it falls between 16 and 21 inches.

Compare it against the chair’s seat height range, which is usually quoted as a span such as 17.5 to 21 inches. If your figure is outside that span, the chair does not fit you, and no other feature compensates.

3. Seat depth

From the back of your hip to the back of your knee, sitting upright. Subtract two to three inches — that is the seat depth you want, leaving a gap behind the knee so the seat edge does not press on the back of your leg.

Most office chairs have a seat depth between 17 and 20 inches. A seat that is too deep is the most common cause of people perching forward and losing all the back support they paid for.

4. Back height and lumbar position

Measure from the seat surface to the top of your shoulder blades. A mid-back chair supports to about there; a high-back chair supports the shoulders and, with a headrest, the neck.

Then measure from the seat to the small of your back — the inward curve, usually 6 to 9 inches up. The chair’s lumbar support needs to reach that point, which is why adjustable-height lumbar matters more than the presence of lumbar support at all.

Putting the numbers together

Work in this order:

1. Set the seat so your feet are flat and your thighs are level.
2. If your elbows are now below the desk, the desk is too high for you. Raise the seat and add a footrest — that is the correct fix, not a taller chair.
3. Set the backrest so the lumbar curve meets the small of your back.
4. Set the armrests so your shoulders are relaxed and your forearms are level.

A chair that cannot be set up this way is the wrong chair, however good it is.

Weight capacity

Every chair has a stated capacity, commonly 250, 300 or 330 lb. It is the specification most listings bury, and it predicts service life better than any other number.

A chair used near its stated maximum every day will wear its gas lift and its base far faster than one used well below it. Choosing a frame rated meaningfully above your weight is not vanity; it is the difference between a chair that lasts five years and one that starts sinking in eighteen months.

Where a chair fails

Almost always one of three places, and all three are worth checking in a specification.

The gas lift. A cylinder that sinks under load. Cylinders are standardised and replaceable on most chairs — worth confirming.

The base. Nylon bases are the norm and are adequate; aluminium bases are stronger and heavier. If a chair pairs a high weight rating with a plastic base, the base is the limit rather than the rating.

The mechanism. The tilt housing under the seat. Cheap mechanisms develop play and creak; better ones are rated for a cycle count.

Armrests

Fixed armrests are set at one height for everybody, which means they are right for a minority. Height-adjustable is the meaningful upgrade. Width and depth adjustment matter for wider or narrower frames.

Flip-up armrests are worth considering if the chair tucks under a desk in a small room — they let the chair go further in.

Finally, the room

Measure the space under your desk, front to back and side to side, and check the chair’s base diameter. A five-star base is typically 26 to 28 inches across, which is wider than people expect and is what stops a chair fitting into a compact workstation.

What we publish

Every chair listed here carries the seat height range, the seat depth, the back height, the weight capacity and the base diameter, because those are the five figures that replace sitting in it. If a figure you need is missing, the showroom can measure the chair.

Common questions

What if my desk is too high for me?

Raise the chair until your forearms are level with the desk, then add a footrest so your feet are supported. Lowering the chair to reach the floor lifts your shoulders all day and is a common cause of neck pain.

How do I know if the seat is too deep?

Sit right back. If there is no gap behind your knees — you want two to three fingers — the seat is too deep, and you will end up perching forward and losing the back support entirely.

Does base diameter matter?

In a small workspace, yes. A five-star base is typically 26 to 28 inches across, which is wider than most people expect and is often what stops a chair fitting a compact desk.

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