Which monitor arm — and will it fit your desk?

The monitors are almost always chosen before the arm, which means the one number that sizes the arm is already knowable. Use the weight without the stand. A monitor’s headline weight usually includes its base, and the arm only ever carries the panel. The figure is in the monitor’s technical specifications. An arm sized from the wrong line is sized for the wrong load — and an overloaded arm sags. Align arms are rated for 4.4–19.8 lb per screen on the single and dual arms, and 2.2–13.2 lb per screen on the crossbar with two screens — it is our heavy-duty arm, and with the crossbar left off it carries one larger screen, up to 24 lb at the head.

Then think about how the screens will move. Depth, height travel, tilt and portrait rotation — enough range to share a screen, present from it, and switch between sitting and standing without fighting the arm.

Check the VESA pattern too — the spacing of the four threaded holes on the back of the screen. The arm’s plate has to match it, and it is easiest to confirm from the model number at the same time as the weight. Send us the monitor model and we will check both.

Two screens on one crossbar? Crossbars only line up when the mounting-plate heights match — the same size is not enough, so matched models are the safe choice. Mixed screens can still work with one turned to portrait: we have installed an Align crossbar holding a 32″ screen vertical beside a 27″ horizontal.

Six styles cover nearly every desk we see. The screens and the room choose between them.

Private or executive office. A single arm with a crossbar, clamped toward the corner, carrying two matched screens. The desk has two jobs — long stretches of solo work, and someone sitting across from you — and a crossbar lets you swing both screens out of the sightline for a guest, or turn them to share what is on them.

Open office and panel workstations. Check the gap behind the worksurface first; some panel systems sit tight enough that a rear clamp cannot seat. With the desk against a panel, two screens want sliders (more on that below).

Home office. Usually a single arm. The quick-connect bracket is worth having even for one screen at home.

Customer-facing counter. A pole with compact arms, one screen facing the staff member and one facing the customer — reception, a dealership desk, a point of sale.

Three or more screens. A modular system, usually on a pole, so the screens scale from one column instead of crowding the desk with bases.

Healthcare and industrial. Wall mounting is common, and the conditions vary more than anywhere else. We plan these individually.

A clamp at the desk edge. The fast, clean default. It grips the back edge of the worksurface and needs a little room behind the desk — about 3/8″ for a bare clamp, closer to 1″ for arms with a rear cable clip, like our Align.

A clamp dropped into a grommet. The install we do most. On a well-designed arm the clamp sits at the edge of the base, not the centre, so in a grommet it occupies only part of the hole and the rest stays open for cords. The arm is mounted and the grommet still does its job.

A bolt through the surface — either through a hole drilled where you want the arm, or through a grommet that is already there. The bolt is centred on the base, and that one detail changes everything: bolted through a grommet, the base sits over the hole and covers it entirely. Mechanically fine, but no cable path is left.

It depends on the clamp, not the arm — and the clamp width is a gate before it is a margin. Narrower than the hole and dropping the clamp in is an option; wider, and that method simply is not available. Here are the numbers on our own Align line:

We publish those widths rounded up on purpose. The parts are metric, and we would rather state a number a touch generous than one that reads tighter than the hardware you receive — if we say it fits the hole, it fits the hole.

Bolting through an existing grommet? On the Align, a grommet up to about 3 1/2″ is workable, and smaller is stronger. The plate under the surface is 4 1/2″ × 2″, so in a 3 1/2″ hole it bears on only about half an inch of material at each end, and across its 2″ width it carries nothing. Every inch smaller buys bearing.

Most makers do not publish clamp width, bolt diameter or plate size at all. For any line other than our own, it is a dimension we confirm for you rather than look up.

A grommet is rarely where you would want the arm, and an arm mounted in it competes with the cables for the same opening. So people often choose to drill a single 1/4″ hole exactly where the arm should live and leave the grommet clear for wires. The hole is small enough to be unremarkable in a worksurface, and the plate underneath spreads the load — a small hole is not a weak one. On the Align the bolt-through hardware handles surfaces up to 1 1/2″ thick. Check what sits underneath before you drill: the plate needs clear surface around the hole, away from the edge and any rail or drawer.

Arms mount at the back of the desk, so that is the edge to look at:

• Glass. A clamp will not grip it. You need an existing hole or grommet and bolt-through hardware — glass cannot be drilled on site.
• A rail or apron under the back edge. Anything where the clamp jaw needs to seat can stop it closing.
• A desk tight to a panel. Some panel systems leave no gap behind the worksurface, and a rear clamp cannot seat. Grommet or bolt-through instead.
• Something underneath where the base lands. A drawer, a support rail or a bracket under the edge can block the clamp even when the top looks clear.
• A surface thinner or thicker than standard. The Align clamp takes a worksurface from 0.8″ to 2.4″ thick on the single and crossbar, 0.4″ to 2″ on the dual. Outside that range, this is where bolt-through earns its place.

On a sit-stand desk, the good news is that a height-adjustable desk already leaves the clearance an arm needs to move. Route the cables through the arm’s channels so it moves freely, and mount the power bar under the worksurface so everything plugged in rises and falls with the desk.

Almost every desk sits against a wall or panel, and almost everyone wants two screens side by side. Without sliders, the only way to bring two screens together is to pivot the arms forward — which advances the screens on the person using them, as close as 18″ when a comfortable viewing distance is roughly an arm’s length. Sliders keep the arms folded back and slide the screens across to meet. Nobody connects their eye strain to the monitor arm, which is exactly why we specify it. Our Align dual ships with two sliders as standard — not an upgrade you discover later you wish you had.

A turn limiter stops a screen swinging into the wall. On most lines it is set at install. On the Align it can be engaged at any time, so if the desk moves against a wall next year, the limiter can be set then.

Match the rated range to the screen. Monitors keep splitting lighter and heavier every year, so an arm rated for last year’s screen is not automatically right for this year’s. Check the range against the weight without the stand.

Modularity is lifespan. If a second screen, a larger one or a curved one is likely, a modular platform is reconfigured rather than replaced. That is one of the places we reach past our own Align, which is not modular.

Quick-connect brackets. Lay the screen flat, attach the bracket, slide it onto the arm — nobody holds a monitor in the air while someone else fiddles with screws. Every Align attachment is a standard quick connect.

Align is our own line — and we carry the best arms in the industry alongside it. We built it because the problems we kept running into did not have a clean answer at a sensible price. Every Align ships with the clamp, bolt-through and grommet hardware in the box, so you do not have to know your desk before you order — and the clamp tightens from above with the supplied wrench, so nobody installs it lying under a desk. Whether another line ships its mounts in the box depends on the line; some supply the clamp and grommet mount together, others make the mount a separately priced choice at order time. Either way we settle the desk condition before the order goes in.

Align is not the answer to everything. A wall or panel mount, a worksurface nothing standard will grip, or a platform you can add screens to later can each call for a different line, and we specify those too. Our monitor arm selector walks through the questions in order.

The dimensions on this page are for Ergo Snob Align arms and are published rounded up. Other lines differ, and most do not publish these figures, so we confirm them against your desk before ordering. Screen weights and VESA patterns come from each monitor’s own technical specifications. This guide is general information from Applied Ergonomics.