How to pick a monitor arm — get VESA, load capacity, and the clamp right and you won't end up with a bad one

2026 update: ported from the old VuePress blog. The backbone — what to look at when picking an arm — still holds, but the product links and price ranges are anchored to 2021. Verify current model numbers and prices and swap to the latest equivalents.

Add a monitor arm and the desk surface opens up in one stroke. The space for papers and a drink comes back, and you can move the screen height to match how you’re sitting.

The catch is the price range — anything from cheap to expensive — and a bad pick can lead to a screen that slowly droops, or, in the worst case, won’t mount at all. This piece narrows the call down to three things — VESA, load capacity, and mounting style — assuming you’ll use the arm for long PC sessions.

The short answer — VESA 100×100, 1.5× the load, clamp mount

Short version: a monitor arm is hard to get wrong if it ticks these three boxes.

1. VESA mount: the monitor supports VESA 100×100 mm on the back
2. Load capacity: aim for 1.5× the monitor’s actual weight, with margin to spare
3. Mounting style: clamp mount (clips onto the desk edge)

On budget vs longevity: for the long haul, an Ergotron LX-class gas-spring arm (17,000–25,000 yen); for a short-term try, a cheaper gas-spring model (5,000–10,000 yen). Mechanical-spring arms and bolt-fixed budget models aren’t a great fit for “I’ll be moving it around.”

What a monitor arm is actually for

Short version: to free up the desk surface, and to move the screen height to fit your posture.

The reason: a monitor on its base sits on a stand whose foot juts toward you and eats 30–50% of the desk depth. Swap to an arm and the front of the desk goes completely clear.

Side benefits: it’s harder to topple in an earthquake, cable routing gets cleaner, and aligning multiple monitors gets easier. If you sit alone, head-on, those are bonuses — not the main reason to buy.

VESA mount and clamp vs grommet — terms first

What “VESA mount” means

The screw-hole standard on the back of a monitor. VESA 100×100 mm refers to four screw holes laid out at 100 mm horizontal and 100 mm vertical spacing. Most 22–27-inch monitors support this pattern. At 32 inches and up, you sometimes hit VESA 200×200 mm or another size, so check the monitor’s spec sheet before you buy.

Clamp mount vs grommet mount

• Clamp mount: clips the desktop from above and below, like a clip. Doesn’t scratch the surface, no tools needed. Needs roughly 5 cm of clearance behind the desk edge.
• Grommet mount: bolts through a hole drilled in the desk (or an existing cable hole). You can mount it anywhere on the surface, not just the edge — at the cost of needing a hole.

Most home desks are fine with a clamp mount. Reach for grommet if you want the arm in the middle of the desk, or if your desk sits flush against a wall with no clearance for a clamp.

Mounting style — clamp is the safe default

Short version: pick a clamp mount and you’ll almost never run into trouble on a home desk.

The reason: no hole in the desktop means it works in a rental, and it travels well through moves and layout changes. Grommet mounts assume drilling, which leaves a permanent mark when you sell the desk.

When clamp fits

• A rental where you don’t want to modify the desktop
• A desk 65 cm deep or more (room for the clamp’s overhang)
• You want the monitor at the back edge of the desk

Almost every home PC desk meets these conditions.

When grommet fits

• The desk already has a cable hole
• You want the desk flush against a wall (the clamp would foul the wall)
• You want the monitor closer to the center of the desk

It’s more common on office desks and standing desks with built-in cable holes.

Load capacity — 1.5× the monitor’s actual weight

Short version: budget for 1.5× the monitor’s actual weight and the screen won’t droop later when the gas spring weakens.

The reason: gas-spring arms rely on internal gas pressure to hold the weight. Run one near its upper limit and as the pressure drops over time, it can no longer hold the screen up. At the upper limit, you tend to hit “wait, when did the screen sag?” within six months to a year.

Rough weights by size

• 22–24 inches: 3–4 kg
• 27 inches: 5–7 kg
• 32 inches: 7–10 kg

So 24 inches calls for an arm rated 5–6 kg or more, and 27 inches for 8–10 kg or more, to keep that 1.5× cushion.

Go by weight, not size

Product specs often say something like “supports up to 27 inches,” but that’s a rough guide. Two 27-inch monitors can differ by 2× in weight, so always check the actual weight on the monitor’s spec sheet and match it against the arm’s load rating.

Movement type — gas spring is the default

Short version: pick gas-spring if you’ll change height often. For fixed positions, mechanical spring or bolt-fixed is fine, but the price gap is only 1,000–2,000 yen, so gas-spring is the safer default.

The reason: gas-spring arms move with one hand, mechanical-spring arms need finicky tension adjustment, and bolt-fixed arms need a tool. People who tell themselves “I won’t move it” usually end up wanting to change the height when their posture shifts — so something that moves easily lasts longer in practice.

Gas spring / mechanical spring / bolt-fixed

• Gas spring: held by internal gas pressure. Moves with one hand. The most common type.
• Mechanical spring: held by a metal spring. Cheaper than gas, but you tune the tension with an adjustment screw. Works if the weight matches the setting, but the screen weight changes mean re-tuning.
• Bolt-fixed: joints locked with hex bolts. Set it once and don’t move it. Cheapest of the three, but a poor match for changing posture.

Price bands and product comparison

Short version: the range runs 5,000 to 25,000 yen. Ergotron LX for the long haul, a cheap gas-spring for a short-term try, bolt-fixed for a static setup — those three slots cover most of it.

For long-term use, the warranty length and parts availability matter. Budget models tend to be “if the gas pressure dies, replace the whole arm.”

Recommended monitor arms (for reference)

The picks below are from 2021. Verify current model numbers and prices and swap to the latest equivalents.

For the long haul — Ergotron LX

Gas-spring, rated to 11.3 kg, wide range of motion, long warranty. Around 20,000 yen up front, but if it sits on the same desk for five years or more, the per-year cost drops.

For a short-term try — Amazon Basics class gas-spring

The Amazon Basics monitor arm, reputed to be the Ergotron LX OEM, is the headline pick. Around 10,000 yen, with load capacity and range of motion both more than enough.

I’ve run a few equivalents over several years and never hit a fatal issue. If you’re going in with the “good enough” mindset, this band is plenty.

FAQ

Q. Can I use one with a monitor that doesn’t support VESA? A. Some makers sell VESA conversion adapters separately. But the stand mount on the back of a monitor is model-specific, and if no adapter exists for yours, you can’t really use it. The reliable move is to check the monitor’s spec sheet for VESA support before you buy.

Q. Will a clamp mount work on a thin desktop? A. The clamp lists a supported thickness range (for example, 10–60 mm). Too thin and the clamp won’t bite, so it ends up loose. Too thick and it won’t close. Measure the desktop and check the range.

Q. For dual monitors, should I pick a single arm that holds both screens? A. A one-arm dual-screen setup looks tidy, but the load capacity and range of motion get tight. For the long haul, two single arms side by side handle future swaps and single-screen use more gracefully.

Q. Will a monitor on an arm wobble? A. With the clamp tightened properly and a desktop of decent thickness and material (plywood or steel), typing-level vibration almost never shows. Very thin or hollow desktops do shake — swap the desk or move to a bolt-fixed arm.

Wrapping up

A monitor arm is hard to get wrong, regardless of price band, as long as it ticks three boxes: VESA 100×100 mm support, load capacity at 1.5× the monitor’s actual weight, and a clamp mount.

For the long haul, Ergotron LX-class is the realistic call; for a short-term try, an Amazon Basics-class gas-spring arm is enough. Mechanical-spring and bolt-fixed arms are on the table if you’ll keep the screen in one place.

The cleaner order is: pick the monitor first, then match the arm to it. The monitor side of the call is covered in a separate piece (How to pick a PC monitor — three things you can’t get wrong, plus one to taste).