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

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 and a warranty. Capacity, screen size, and VESA range follow from the HX’s stronger spring and beefier joints. Reach and lift differ too, and both favour the LX.

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, and it keeps the longer reach. Above 20 lbs the LX’s low-travel restriction applies, so if the screen has to sit low, check that the HX’s 11.5 inches of lift still reach your eye height.

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.
• 32–49 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 mechanical spring (not a gas cylinder) 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)
• Vertical adjustment: 13” range
• Reach (from pivot to screen): 25”
• Tilt: 70° (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 covers both a desk clamp for desktops 0.4”–2.4” (10–60 mm) thick and a grommet mount for holes 0.31”–2” wide in desktops up to 3” thick.
• Replacement parts are available individually, and the warranty is honored without drama.

Where it falls short:

• The 34-inch screen limit rules out 45-inch curved gaming panels such as the LG 45GR95QE-B on size alone, whatever they weigh. A 22 lb panel such as the MSI MAG 321CUP fits the weight range but sits near the top of it, where the LX can lose up to 4.5” of low travel.
• 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, at the cost of a little reach and lift.

Spec sheet (from ErgoDirect’s 45-475-026 listing):

• Weight capacity: 20–42 lbs (9.1–19.1 kg)
• Screen size: up to 49”
• Vertical adjustment: 11.5” range
• Reach: 23.6”
• Tilt: 70° (back) / 5° (forward)
• Pan: 180°
• Rotation: portrait/landscape
• VESA: 75×75, 100×100, 200×100, 200×200
• Warranty: 10 years
• Color: matte black, polished aluminum, white

Where the HX excels:

• Rated to 42 lbs and 49 inches, it covers the heaviest and widest single displays of the three. For the deepest curved panels, ErgoDirect notes that Samsung’s 49-inch Odyssey G9 needs Ergotron’s separate HX Heavy-Duty Tilt Pivot.
• Takes every common VESA pattern from 75×75 to 200×200.
• Same 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.
• 23.6” of reach and 11.5” of lift, against 25” and 13” on the LX.
• Pans through 180° rather than the LX’s 360°.
• 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 23.6 on the HX.

Spec sheet (from the Ergotron MX product page and ErgoDirect’s 45-214-026 listing):

• 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, 200×100, 200×200
• 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.
• Lists the same VESA range as the HX, 75×75 through 200×200, on a shorter arm.

Where it falls short:

• 16.7” of extension against 25” on the LX and 23.6” on the HX, so it cannot push a panel back on a deep desk.
• 5” of vertical travel against 13” on the LX and 11.5” on the HX.
• The 30” screen limit means many large 200×200 displays exceed it even though the plate fits.
• 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, and a 22 lb ceiling, below the LX’s 25. 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: Very expensive, and the M2.1 in particular is rated well below the LX.
• 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 from Ergotron’s product pages and ErgoDirect’s listings; HX and MX figures corrected October 2026. Pricing is approximate manufacturer/Amazon listing as of publication.