A buyer's guide to armrest adjustability

The baseline is height adjustment — armrests that move up and down so your shoulders can stay relaxed instead of hunched or shrugged. Any chair marketed as ergonomic should have at least this.

2D armrests add width adjustment (pivoting in or out), useful if your shoulders are narrower or wider than average. 3D armrests add depth (forward/back), which helps when typing versus resting your arms changes how far forward you need support. 4D armrests (Steelcase's Gesture is the reference point) add a pivoting motion that follows your forearm as you reach for a phone or tablet off to the side.

More axes of adjustment aren't automatically better if you never touch them — most people set armrests once and forget them. Where 4D genuinely pays off is if you regularly switch between a keyboard, a tablet, and handwriting at an angle during the day.

One thing that matters more than axis count: armrests that get in the way of pulling the chair fully under a desk are a common complaint on wider designs. If your desk has a low apron or drawer, check the armrest width and retracted position before buying, not just the adjustment range.