Monitor Arms, Rated at Both Ends

A Monitor Too Light Will Not Stay Down

The whole category is sold by its maximum weight. The number behind the returns is the minimum, and most listings do not publish it.

Four Point Four Pounds Is a Floor, Not a Detail

Start with the physics. A spring arm is bought tensioned for a range. The HUANUO FlowLift and the Amazon Basics gas spring arm declare 4.4 pounds as their minimum, and so does Acer. Put a 24 inch monitor that weighs 6 pounds without its stand on an arm set for a heavier screen, or a lighter panel on one whose floor is above it, and the spring wins: the arm rises on its own every time you let go. It is not broken, it is out of range at the bottom. The light monitor is the most common problem in the category and the one least explained.

This table publishes both numbers in separate columns, minimum and maximum, and marks the listings that do not declare a minimum, which are the majority, instead of leaving the cell empty. The missing figure is information, and it is shown as such.

A third column resolves the weight of a bare panel for the usual sizes, which is what actually hangs from the arm: a 24 inch is about 6 pounds, a 27 inch 9, a 32 inch 13 and a 34 inch ultrawide 17. With that you see at once whether your monitor falls inside the range or below it.

• The clamp: none of the listings we checked puts in its title the desk thickness the C-clamp accepts. The usual range is 0.4 to 2.4 inches, and thick melamine or solid wood tops go past it, while desks with a rear rail or a modesty panel leave no room for the clamp at all. The way out is a grommet base, which means drilling the top. The table reads the range from the bullets, one listing at a time, and publishes it.
• The hole that is not there: part of the curved and thin monitors on sale has no VESA holes, or has them at 75 millimeters when the arm plate is 100, or has them recessed and needs spacers. The arm solves nothing if the monitor has nowhere to screw it. The table gives the pattern each arm takes, 75, 100 or both; an adapter is always a separate purchase.

An arm holds a panel when the size is in its screen range and the bare weight is between its minimum and its maximum. Arms that declare no minimum are counted on the maximum alone.

24" panel27" panel32" panel34" ultrawide

The Minimum Weight Two Thirds of Listings Omit

Weigh the monitor without its stand, or look up the "weight without stand" in its manual. If the arm declares a minimum, that figure must be at or below your panel. If it declares none, the safe reading is that it is tuned for something near the middle of its range, and a light 22 or 24 inch panel may not hold position. Mechanical spring arms usually have a narrower range than gas springs and need the tension set more carefully.

Of the 159 arms in this table, 116 (73%) publish no minimum weight anywhere in the listing, and 43 do. The median declared floor is 4.4 lbs. The lowest floors:

Declares a minimumFloor under 4 lbsDoes not declare

Will the Clamp Fit Your Desk

Measure the desk top at the edge where the arm will go, and look under it. The clamp needs a flat lip about 2 to 3 inches deep with nothing in the way: a frame rail, a drawer, a keyboard tray or a modesty panel at the back all block it. Glass tops and thin particleboard can crack under the pressure of a clamp holding a heavy screen out at full reach. If you are still choosing the desk, the computer desks measured by usable depth show how much room you keep in front of the monitor.

126 of the 159 arms also bring a grommet base.

Up to 1"Up to 1.6"Up to 2.4"Grommet base

VESA 75 and VESA 100, and Monitors With No Holes at All

VESA is the square of four threaded holes on the back of the monitor, 75 or 100 millimeters apart. Most arm plates take both. Before buying, check three things on your monitor: that the holes exist at all, which many thin and some curved models leave out; which spacing they use; and whether they sit in a recess, in which case you need the spacers that usually come in the screw bag. Monitors without holes need a clamp style adapter bought separately.

75x75100x100Both

Reach, Height Travel and the Wall Behind Your Desk

Reach is how far the plate can move from the clamp, usually 15 to 25 inches. On a desk pushed against a wall the arm also needs room to fold behind the monitor: an arm that folds back 6 inches will not let the screen sit flush if the desk is only 24 inches deep. Height travel decides whether the top of the screen can reach eye level; standing desk users need the most. Not every listing gives both figures, and the table shows a question mark where one is missing.

Reach 20" or more

Gas Spring Against Mechanical Spring

A gas spring is a sealed cylinder: it moves smoothly, holds a wide range of weights, and its tension is set with a hex key. A mechanical spring arm uses a coil, is often cheaper and lasts long, but its range is narrower, so getting the floor right matters even more. Arms with neither are pole mounts that move only when you loosen a knob. In both kinds, set the tension with the monitor attached and the arm level.

Gas springMechanical spring

One Arm, Two Arms or a Stacked Pair

On a dual arm each side has its own spring, and the weight range is per arm, so two different monitors are fine as long as each falls in the range. Side by side pairs need the clamp near the middle of the desk and about 50 inches of width for two 27 inch screens; stacked pairs share one pole and put the upper screen high, which suits tall users and standing desks. A laptop tray takes the place of one screen and holds the laptop closed or open beside the monitor.

SingleDual side by sideStackedLaptop tray

Arm or Platform

An arm frees the whole desk under the monitor and lets you move the screen during the day, but it needs a desk edge it can clamp to and a monitor with VESA holes inside its weight range. A platform needs nothing but a flat surface, takes any monitor on its own stand, and lifts it a fixed amount. If the clamp does not fit or the monitor has no holes, the monitor stands sorted by the clearance underneath are the simpler fix.

What We Exclude From This Table

Every listing is checked by its ASIN data, never by its title. The minimum weight and the clamp range are in no headline, so they are read from the bullets and the specification one by one. The catalog for these searches brings in other products: a full motion TV wall mount sits second among the first results for "monitor arm", with a dual ultrawide wall mount fifth and a magnetic arm for portable monitors tenth. Left out:

• Platforms and risers that stand on the desk, with no clamp or grommet, which go to /monitor-stand/.
• Sit to stand converters, which go to /standing-desk-converter/.
• Wall and ceiling mounts for televisions, which go to /tv-mount/.
• Laptop stands that sit on the desk, which go to /laptop-stand/.
• Holders for 13 to 18.5 inch portable monitors with their own adapter, which take no desk panel.
• Tablet, phone, microphone and webcam holders.
• VESA adapters, spacers and screw kits sold alone.
• Arms for three or more screens.
• Any listing that declares neither a maximum weight nor a VESA pattern.
• Lots of several units.

Laptop trays on an arm stay in, with their own filter, when they clamp to the desk and share the columns. The VIVO STAND-V001L is the typical case.