Ergotron LX vs HX: Which One Fits Your Monitor?

The short answer to Ergotron LX vs HX vs MX: choose the LX for most monitors up to 25 lbs, the HX for heavy ultrawides and large displays up to 42 lbs, and the MX for the 25 to 30 lb band or the nicer materials, provided its shorter reach suits the desk. They look almost identical from across the room, but each is built for a specific weight and screen-size range, and picking the wrong one means sag or a wobbly arm.

Below is the full spec breakdown, the LX vs HX head-to-head that most people are actually here for, the curved-monitor caveats, and a decision tree so you can match the arm to your exact monitor. For the wider field beyond Ergotron, see the ranked guide to the best monitor arms of 2026.

Ergotron LX vs HX vs MX at a glance

Spec	LX	HX	MX
Weight capacity	7–25 lbs	20–42 lbs	14–30 lbs
Screen size	up to 34”	up to 49”	up to 30”
Reach	25”	25”	16.7”
VESA	75×75, 100×100	100×100, 200×100, 200×200	75×75, 100×100
Tilt	75° / 5°	75° / 5°	75° / 5°
Warranty	10 years	10 years	10 years
Best for	most monitors up to 25 lbs	heavy ultrawides up to 42 lbs	25–30 lbs, premium build

Choose the LX for most monitors up to 25 lbs, the HX for heavy ultrawides and large displays up to 42 lbs, and the MX for panels in the 25 to 30 lb band that do not need to sit far back.

Ergotron LX vs HX: the head-to-head

The LX and the HX are the two arms most people are actually cross-shopping, and they share a mechanism, a reach, and a warranty. Only three specs separate them, and all three follow from the spring.

Spec	Ergotron LX	Ergotron HX	What it means
Weight capacity	7–25 lbs	20–42 lbs	The whole decision. Under 20 lbs the HX cannot hold; over 25 lbs the LX cannot.
Max screen size	34”	49”	The HX is the only one of the two rated for 38”+ and super-ultrawide panels.
VESA	75×75, 100×100	100×100, 200×100, 200×200	Large displays with a 200×200 pattern will not bolt to an LX at all.
Reach	25”	25”	Identical. Reach is never the reason to choose between these two.
Vertical travel	13”	13”	Identical on paper; both lose some low travel near the top of their load range.
Mechanism	Constant Force spring	Constant Force spring, stronger	Same feel, same hex-key tensioning, different spring rate.
Warranty	10 years	10 years	Identical.
Relative price	baseline	roughly 50% more	You are paying for spring rate and VESA range, not for a better joint.

The overlap band is 20 to 25 lbs, and inside it either arm works: the LX runs near the top of its range, the HX near the bottom of its. If the monitor sits at 22 lbs and might be replaced by something heavier later, the HX is the safer buy. If it sits at 22 lbs and the next monitor will be smaller, the LX is the cheaper one.

Outside that band there is no judgement call. Under 20 lbs the HX spring will not stay compressed and the monitor drifts up; over 25 lbs the LX spring cannot hold it down. Weigh the panel without its stand first — published figures for every common screen size are listed in monitor weight by size — because the boxed weight includes 4 to 8 lbs of stand and will push you into the wrong arm. If your current arm already drifts, diagnose it with monitor arm drifting or sagging before assuming you need a different model.

Quick Verdict by Monitor Type

• 24–32 inch flat or curved, up to 25 lbs: Ergotron LX (Amazon Associates). The default, the most common, the one you should buy if you don’t have a reason to upgrade. Full detail in the Ergotron LX review.
• 32–43 inch curved or heavy-gaming, 20–42 lbs: Ergotron HX (Amazon Associates). The upgrade path for heavy ultrawides.
• Up to 30 inch, 25–30 lbs, sitting close to the desk edge: Ergotron MX. Premium build and rated past the LX’s 25 lb ceiling on a smaller frame than the HX, but it extends just 16.7 inches.

Ergotron LX — The Default

The LX is Ergotron’s mid-range single-arm and one of the best-selling monitor arms in the western market. It uses Ergotron’s Constant Force tension system, a gas-spring-style internal mechanism that holds position without thumbscrews (see gas spring vs mechanical spring arms for why that matters), and supports monitors from 7 to 25 lbs.

Spec sheet:

• Weight capacity: 7–25 lbs (3.2–11.3 kg)
• Screen size: up to 34” (Ergotron’s official spec; owners commonly report mounting 38” ultrawides that stay under the 25 lb limit)
• Vertical adjustment: 13” range
• Reach (from pivot to screen): 25”
• Tilt: 75° (back) / 5° (forward)
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 75×75, 100×100
• Warranty: 10 years
• Color: matte black, polished aluminum, white

Where the LX excels:

• Constant Force tension is genuinely set-and-forget. Once tuned to your monitor, it stays in position for years.
• Mounting hardware accommodates both desk clamp (1.4”–2.4” desktop thickness) and grommet mount (0.4”–2.4”).
• Replacement parts are available individually, and the warranty is honored without drama.

Where it falls short:

• The 25 lb ceiling is below the heaviest 32-inch and 45-inch curved gaming monitors. The LG 45GR95QE-B weighs 36 lbs, well past it. A 22 lb panel such as the MSI MAG 321CUP fits, but sits near the top of the range where spring arms drift soonest.
• Reach is 25” — adequate for desks 27”+ deep, marginal for shallow desks.

Buy: Ergotron LX single monitor arm (Amazon Associates). Matte black, polished aluminum, and white finishes are all listed; pricing is broadly identical across them.

Ergotron HX — Heavy-Duty Single

The HX uses the same Constant Force mechanism but with a stronger spring and beefier joints. Capacity nearly doubles to 42 lbs.

Spec sheet:

• Weight capacity: 20–42 lbs (9–19 kg)
• Screen size: up to 49”
• Vertical adjustment: 13” range
• Reach: 25”
• Tilt: 75° / 5°
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 100×100, 200×100, 200×200
• Warranty: 10 years
• Color: matte black, polished aluminum, white

Where the HX excels:

• Handles the heaviest single-monitor setups on the market. Its rated 42 lb capacity covers 49-inch ultrawides like the ~36 lb Samsung Odyssey G9 with margin to spare, which is the class of display owners most often report pairing with the HX.
• Supports VESA 200×200, which most large displays require.
• Same intuitive Constant Force tension as the LX.

Where it falls short:

• For monitors under 20 lbs, the HX is overkill. The Constant Force spring requires a minimum load to work properly — a 12-lb monitor on an HX may droop or fail to hold position.
• Costs ~50% more than the LX.

Buy: Ergotron HX heavy-duty monitor arm (Amazon Associates). This is the standard-pivot desk mount; the HD-pivot gaming and wall-mount variants are separate products.

Ergotron MX — Premium Build, 30 lb Ceiling

The MX is the premium pick. Same Constant Force system, but the build is meaningfully nicer, with milled-aluminum joints rather than cast, and the rated ceiling is 30 lbs, five above the LX. The trade is reach: the MX extends 16.7 inches against 25 on the LX and HX.

Spec sheet (from the Ergotron MX product page):

• Weight capacity: 14–30 lbs (6.4–13.6 kg)
• Screen size: up to 30”
• Vertical adjustment: 5” range
• Reach: 16.7” (shortest of the three)
• Tilt: 75° / 5°
• Pan: 360°
• Rotation: portrait/landscape
• VESA: 75×75, 100×100
• Warranty: 10 years
• Color: matte black, polished aluminum

Where the MX excels:

• The 14 to 30 lb band covers panels the LX cannot hold and the HX only handles at the very bottom of its range.
• Takes 75×75 as well as 100×100, a pattern the HX does not offer.
• Reviewers consistently rate the milled-aluminum joints a step above the cast parts on the LX and HX.

Where it falls short:

• 16.7” of extension against 25” on the LX and HX, so it cannot push a panel back on a deep desk.
• 5” of vertical travel against 13” on the other two.
• No 200×200 VESA, so the largest displays will not bolt to it.
• Costs about 2x the LX.

Buy: Ergotron MX.

The Decision Tree

Ask three questions in order:

1. Is your monitor over 30 lbs? If yes → HX. If no, continue.
2. Is it between 25 and 30 lbs? If yes → MX, or HX if the panel also has to sit further back than 16.7 inches. If no, continue.
3. Do you want the premium build and can you live with 16.7 inches of reach? If yes → MX. Otherwise → LX.

99% of single-monitor home office users buy the LX. The HX is for heavy ultrawide or large display users. The MX covers the 25 to 30 lb band and the buyers who want the nicer materials, provided the shorter reach and shorter height range suit the desk.

Curved Monitor Caveats

Curved monitors complicate VESA mounting. The center of gravity is closer to the screen face than on a flat monitor, which puts unusual torque on the arm joint.

• For curved monitors with 1500R or shallower curvature, no adjustment needed.
• For 1000R or deeper (like Samsung Odyssey or LG UltraGear curved): consider a VESA spacer adapter. The standard Ergotron mount works but the screen tilt range is reduced.
• 49” super-ultrawide curved displays: HX only, and use a VESA reinforcement plate. The pivot point is far enough from the screen center to create persistent sag without a reinforcement.

For a wider field of options beyond Ergotron at this size, see the dedicated ultrawide and heavy monitor arm guide.

Dual-Monitor Setups

None of these arms is a dual-monitor arm by default. For dual monitors, see:

• Ergotron LX Dual Side-by-Side (Amazon Associates): two LX arms on one post. Best for two 24-inch monitors.
• Ergotron LX Dual Stacking (Amazon Associates): vertical stacking, useful for trading-style setups.
• For two monitors past the dual mount’s per-arm rating (check the listing; it is lower than the single LX’s 25 lbs): two separate HX arms, mounted independently.

What About Non-Ergotron Alternatives?

Several brands compete with Ergotron:

• Herman Miller Flo Plus: Cleaner aesthetic, more expensive, capacity is 22 lbs (between LX and HX). The lighter-duty single-arm Herman Miller Flo (Amazon Associates) sits below it. For a closer look, see Herman Miller Flo vs Humanscale M2 vs Ergotron LX.
• Humanscale M2.1/M8.1: Best-in-class joint smoothness, very expensive, lower capacity than Ergotron’s lineup.
• Herman Miller Jarvis: The former Fully Jarvis, now sold under Herman Miller after Fully wound down. Lists around $175 with a 20 lb ceiling and the same 10-year warranty as the LX.
• Amazon Basics Premium Monitor Arm: Surprisingly competent for the price (~$80), but only 17 lbs capacity and shorter warranty.

For most users, Ergotron is the right pick — the LX in particular. The 10-year warranty, parts availability, and the Constant Force mechanism are difficult to beat at the price.

Related Reading

• How to choose a monitor arm — the full buying decision
• VESA compatibility explained — mounting patterns and adapters
• Sister site StandDeskReview — for the desks these arms attach to
• Sister site ErgoRanker — for spec-driven ergonomic rankings

Final Word

If you’re stuck deciding between Ergotron LX, HX, and MX, the answer is almost certainly the LX. The HX exists for heavy ultrawides; the MX exists for the 25 to 30 lb band and for premium-material preferences. Most home offices need neither. Confirm the call against your own panel with the Monitor Arm Fit Checker.

Specs verified May 2026. Pricing is approximate manufacturer/Amazon listing as of publication.