VESA and weight ratings, explained

VESA is the Video Electronics Standards Association, and the standard everyone means when they say “is it VESA?” is the Flat Display Mounting Interface— FDMI. It is the reason a monitor from one company bolts onto an arm from another, and on the whole it works so well that nobody thinks about it until it does not.

Then it fails, and the reason is almost always one of three misconceptions that are repeated everywhere, including in places you would expect to be reliable. Let us do the useful thing first and say what the standard actually contains — read from VESA’s own document, which is free.

What VESA's own document says

FDMI covers displays from 4″ to 90″ diagonal and splits them into parts. Here is what VESA publishes for each, verbatim from their FDMI Overview:

• Part A— “Open, Future”. Reserved. It is not a mounting pattern, it is a placeholder, and it is why lists that start at B are not missing anything.
• Part B— 4″–7.9″, “weighing up to 2 kg (4.4 lbs.)”. A four-hole interface.
• Part C— 8″–11.9″, “weighing up to 4.5 kg (10 lbs.)”. A four-hole interface.
• Part D— 12″–22.9″, “weighing up to 14 kg (30.8 lbs.)”. Four-hole, and VESA specifies “either of the specified center mounted, four-hole mounting interfaces” — note either of, which is the standard quietly confirming there are two.
• Part E— 23″–30.9″, “weighing up to 22.7 kg (50 lbs.)”. A six-hole interface.
• Part F— 31″–90″, “weighting up to 113.6 kg (250 lbs.)”. A multi-hole interface.

Read that list again and notice what is notin it: the millimetres. No 75×75. No 100×100. No 200×200. VESA’s free Overview defines every part by diagonal and weight, then points at sections of the full standard for the actual hole geometry.

An honest note about where the millimetres come from

This matters enough to interrupt the guide for.

The full FDMI standard is free, but it sits behind a form. We have not read it. So when you see the familiar mm patterns lined up against VESA parts — here or anywhere else — you are almost always reading a manufacturer’s implementation reference, not VESA’s document.

The mapping below is Ergotron’s. It is widely used, it is consistent with everything VESA does publish, and it matches what the monitor manufacturers themselves state — Humanscale’s M2.1 manual, for instance, says plainly that “The VESA Bracket features 75mm and 100mm hole patterns”, which is exactly what MIS-D is supposed to be. We have no reason to doubt it and every reason to use it.

But it is Ergotron’s, and this site does not launder one organisation’s numbers into another’s. The weights and diagonals below are VESA’s. The millimetres are Ergotron’s. Where those two sources disagree — and in one place they do — we will show you the disagreement rather than pick a winner quietly.

The FDMI parts

Diagonal and weight: VESA’s FDMI Overview. Hole patterns: Ergotron’s VESA guide.

• MIS-B— 4–7.9″ · up to 2 kg / 4.4 lb · 50 × 20 mm
• MIS-C— 8–11.9″ · up to 4.5 kg / 10 lb · 75 × 35 mm
• MIS-D— 12–22.9″ · up to 14 kg / 30.8 lb · 75×75 or 100×100 mm
• MIS-E— 23–30.9″ · up to 22.7 kg / 50 lb · 200 × 100 mm, six-hole
• MIS-F— 31–90″ · up to 113.6 kg / 250 lb · 200 mm increments, square from 200×200

Three things nearly everyone gets wrong

1. 200×200 is MIS-F, not MIS-E

This is the big one, and you will find it wrong on retailer listings constantly. MIS-E is 200×100. The square 200×200 layout belongs to MIS-F, which is the large-display part.

It is easy to see how the confusion starts — E comes before F, 200×200 looks like a step up from 100×100, and both are “the big ones”. But they are different interfaces on different parts of the standard, and if you buy a bracket for the wrong one it will not bolt on.

2. MIS-E has six holes

Everyone assumes four, because MIS-D has four and MIS-D is what almost everyone owns. VESA’s own text for Part E specifies a “six-hole mounting interface”— centre-mounted, edge-mounted, or both.

So “my arm is VESA, my monitor is VESA” can still end with an arm that physically cannot attach, because one of them is speaking four-hole and the other six. This is the practical reason the heavy-panel arms page makes a point of the Ergotron HX supporting MIS-D, E and F: at large sizes the pattern stops being a formality.

3. MIS-D means both 75×75 and 100×100

People treat these as separate standards. They are one part. MIS-D covers both, which is why arms are described as “MIS-D, 100/75” — supporting the pair, not choosing between them.

VESA’s wording supports this even without the millimetres: Part D calls for “either of the specified center mounted, four-hole mounting interfaces”. Either of only makes sense if there are two, and the two are the 75 and the 100.

In practice this is good news: nearly every monitor arm sold ships a bracket drilled for both, so a 75×75 monitor and a 100×100 monitor use the same arm and different holes.

Decoding "MIS-D, 100/75, C"

You will meet this string on spec sheets and it looks more forbidding than it is. Three fields:

• MIS-D— which part of the standard. Here: displays 12–22.9″, up to 14 kg.
• 100/75— the hole patterns supported, in mm. Both 100×100 and 75×75.
• C — centre-mounted. The holes are in the middle of the panel’s back. VESA’s Overview defines Center Mounting and Edge Mounting implementations separately, and an edge-mounted display puts the interface out at the panel’s edge instead.

So “MIS-D, 100/75, C” reads: a centre-mounted four-hole interface, in either the 100mm or 75mm square pattern, for a display in the 12–22.9″ band. The notation is Ergotron’s convention; the parts it references are VESA’s.

Where Ergotron's own table slips a digit

One small thing, worth reporting plainly and without a fanfare, because it is the kind of error that quietly propagates.

Ergotron’s VESA guide gives MIS-E as supporting up to “50 lbs (23.7 kg)”. But 50 lb is 22.7 kg, not 23.7 — and 22.7 kg is exactly what VESA’s own document says for Part E.

So this is almost certainly a typo: one digit, 2 becoming 3, on a page that is otherwise the most useful public reference on this subject and the source of the millimetres we are using ourselves. The pound figure is right, the kilogram figure is a keystroke out, and if you have been quoting 23.7 kg you got it from here.

We are flagging it for one reason only: this site’s whole position is that numbers should be traceable to whoever published them. Tracing this one is what surfaced the mismatch. It is not a scandal and it does not make Ergotron’s reference less useful — it is just what checking looks like when it works.

What VESA does not promise you

This is the part that decides whether your purchase works, so it is worth being blunt about the standard’s limits.

VESA does not promise your arm can hold the monitor. The part weights above describe what the mounting interfaceis specified for. They are not your arm’s rating. Your arm has its own range — with a minimum as well as a maximum — and it is usually far tighter than the standard’s. A MIS-D monitor can weigh up to 30.8 lb under the standard; the Ergotron LX stops at 25.

VESA does not promise your specific model complied. A standard describes what a conforming display shoulddo. Individual models deviate: recessed mounting points, non-standard patterns, curved backs that need spacers, and screw threads that are technically right and practically too short for the panel’s recess. Humanscale ships extended screws and plastic spacers with the M2.1 for exactly this reason — and a manufacturer including a workaround in the box is a fair signal about how often it is needed.

VESA says nothing about safety or durability.It is a fit standard. It does not mean an arm was tested, cycled, or independently certified — and across every arm on this site, not one claims a third-party standard like UL, ANSI or BIFMA. The cycle figures that do exist are internal.

And the standard does not know your monitor is curved.FDMI defines parts by diagonal and weight; it does not derate for curvature. Some manufacturers do it themselves: Humanscale’s capacity sheet gives the M2.1 5–15.5 lb with a flat panel but only 5–12.5 lb with a curved one. Three pounds, gone to the shape, because a curved panel carries more mass forward of the plate. VESA will not warn you about that. Most manufacturers will not either.

How to actually check compatibility

Four steps, in this order, and the order is the point — most people start at step four and work backwards into a return.

1. Find the hole pattern.Look at the back of the monitor, or find “VESA” on its spec page. Measure the square if you have to: centre to centre, in millimetres. 100×100 and 75×75 are MIS-D and cover the overwhelming majority of desk monitors. Do not infer it from the diagonal.

2. Weigh the panel without its stand.This is the number the arm sees, and it is the one nobody looks up. The spec page calls it “weight without stand”.

3. Check that weight against both ends of the arm’s range. Under the minimum, a counterbalanced arm floats up and will not stay down. Over the maximum, it sags. Both are unfixable by adjustment, and the minimum is the one nobody warns you about.

4. Only now look at screen size.Arms publish a max diagonal (34″ on the LX, 49″ on the HX) and it is a real limit, mostly about leverage and the panel fouling the arm. But it is the lastcheck, not the first, and treating it as the first is how people end up with an arm that fits their 27″ perfectly and cannot hold it up.

Once those four line up, the arm will fit. Then the question becomes which arm you want, which is a mechanism question, and which one is worth the money, which is a roundup question.