Armrests are usually set too high

An armrest has one legitimate job: to be where your forearms already are, so that when you rest on it nothing about your shoulders changes. Anything higher than that is lifting your shoulders for you, all day, and you won’t notice because the sensation arrives hours later and several body parts away.

Armrests get set once — at the factory, usually at the top of their range — and then are never touched again. They are one of the highest-yield ten-second adjustments in a desk setup, and they’re one of the few places where removing the object entirely is often the right answer.

What “too high” does

Two separate compensations, and most people with badly set armrests are doing both.

Your shoulders sit lifted. If the armrest holds your elbow above the height your relaxed arm would hang to, your shoulder is elevated by the chair. You aren’t holding it up, so there’s no effort you can feel — the arm is genuinely resting — but the joint is parked away from the middle of its range for eight hours, and the tissue around it notices even if you don’t. This is the version that produces the tight-shoulders-and-neck feeling that people take to be a monitor problem.

The chair can’t get close to the desk. This is the sneakier cost. Tall armrests collide with the desk edge or the apron beneath it, and the chair simply stops. You end up sitting a hand’s width further out than you should, which puts the keyboard and mouse that much further away, which means you reach. So one bad setting produces both lifted shoulders and forward reach, and if you go looking for the cause of the reach you’ll find it at the keyboard and fix the wrong object.

ARMREST HEIGHT — the check
  Sit fully back. Let both arms hang straight down, completely slack.
  Now bend your elbows to bring your hands to the keyboard,
  without lifting your shoulders at all.

  · Armrests just brush your forearms there   → height is right
  · You have to lift your arms to reach them   → too high
  · Your elbows rest on them and your shoulders
    are visibly higher than when hanging        → too high
  · They're a clear distance below your arms    → too low, harmless
  Then: pull the chair in as far as it goes. Do the armrests
  hit the desk before your body is close to it?

Too low is a non-problem. An armrest below your arms does nothing; you ignore it and lose nothing. That asymmetry is why the correct direction to err in is down, and why “lower them until you’re not sure they’re there” is decent default advice.

Setting the ones that adjust

Height first, then width, then angle, then whether you want them at all.

Height. Lower until they just contact your relaxed forearms in the working position. Do this with your hands on the keyboard, not with your arms in your lap — the check has to happen in the position you’ll be in.

Width. If they move in and out, bring them in until your arms are hanging naturally rather than splayed. Wide-set armrests make you abduct your arms slightly to use them, which pulls your hands away from the keyboard’s centre and out toward the sides.

Depth and angle. Some pads slide forward and back or pivot. The useful setting is one where the pad supports the forearm rather than jamming into the point of the elbow, and where the pad doesn’t sit so far forward that it stops the chair advancing. Point them very slightly inward if they pivot; it tends to follow the line the forearms actually take.

Then check the desk clearance again, because you’ve changed the height and they may now go under the desk edge, which changes how close you can sit and therefore where the keyboard should be. Redo the reach.

The fixed-armrest problem

A great many chairs have armrests that don’t move — moulded into the shell, or bolted at one height. Frequently that height is too high, and frequently it’s also too far forward.

The options, in order:

Remove them. More chairs allow this than people assume. Look underneath the seat and behind the backrest for bolts; four bolts and a hex key is the common case. A task chair without armrests is a perfectly good chair, and if it means you can pull it fully under the desk, it’s a better one. Keep the bolts.

Work above them. If they can’t come off and they’re low enough to clear the desk edge, you can often ignore them entirely — hands to the keyboard, arms not resting on anything. That’s fine. Arms don’t require support; they require not being propped up wrongly.

Pad the desk side instead. If the armrests are unusable and you want somewhere to rest, the desk edge itself can serve, with something soft over it. This is a real solution and it has a trap: leaning your forearms on a desk that’s too high is how you end up with a pressure line across them. If the desk edge is where your arms want to rest, check whether the desk is too high first, because it probably is.

Turn the chair around. Only half a joke. Some armchair-shaped chairs are better used as backless seating with a cushion, but this is edge-case territory.

Chairs sold on their armrests

Two categories worth naming without naming anyone.

Gaming-style chairs frequently have tall, wide, heavily padded armrests as a styling feature, positioned for a reclined seat rather than for a desk. They are the most reliable cause of the can’t-get-close problem, and they are usually removable.

Executive chairs tend to have fixed, sculpted arms, set high, on a chair that also has a deep seat. Both problems at once, and the arms usually can’t come off. This is the one case where the honest answer is that the chair is decorative and a plain task chair would work better.

Both categories are really the same problem: a chair built around a larger-than-average body. If armrests, seat depth and backrest height are all slightly wrong in the same direction, you’re probably outside the body the furniture was sized for, and the answer is a set of small adaptations rather than one adjustment.

Note that no amount of armrest is a feature by itself. Armrests support arms; they don’t do anything for a back, they don’t improve posture, and more of them isn’t better.

What this fixes and what it doesn’t

Getting armrests out of the way removes a reason for your shoulders to be up and lets you sit closer. That’s the whole claim. It doesn’t treat anything, and no chair adjustment does.

A chair with well-set armrests that you sit in for four unbroken hours will still leave you stiff, because that’s duration rather than geometry, and getting up is a different subject.

If you have persistent shoulder or arm pain, or pain that travels down an arm, or numbness, tingling or weakness in a hand, that’s a reason to see a qualified clinician rather than to keep adjusting a chair.

Go and lower them now. It takes ten seconds and it’s the adjustment with the best ratio of effort to effect in the whole setup order.