Two Different Monitors on One Dual Arm: How to Level the Tops

Quick Answer: Measure each screen's top picture edge from the desk, then raise or lower one arm or its pole collar until both tops match.

• Each side moves up and down on its own spring: Set each arm's height and tension separately. Use Fix A to set each arm
• One arm runs out of range, or the arms don't move vertically: Shift that arm on the pole. Use Fix B to move the pole collar
• Both screens hang from one fixed bar: Neither side can move separately. Use Fix C for fixed-bar mounts
• Not sure which edges to match: Go to Step 1 to measure and choose

• Difficulty: Easy on independent spring arms; moderate when a pole collar or mounting plate has to move.
• Tools: A tape measure, painter's tape, and the hex keys supplied with the dual arm.

Jump to:

• Step 1 - Measure Both Screens and Pick the Shared Edge
• Step 2 - Bring Each Screen to the Line
• Step 3 - Check the Tops Stay Level
• Common Mistakes
• FAQ

Why Two Different Monitors Sit Unevenly on the Same Arm

Each monitor hangs from its VESA mounting pattern, and that pattern sits at a different spot on every model. Two arms set to the same height can still leave the screens' tops far apart.

Size adds to it. A larger screen extends further above and below its mounting point, so its top ends higher even when both plates line up.

Weight matters on spring arms. Each side's spring must match its own monitor; a side set for the wrong weight drifts away from the height you just set.

Problem state: The mounting plates line up, but the picture edges don't, because the monitors differ in size and VESA position.

Corrected state: The plates sit at whatever heights it takes for the picture edges to line up, and each side's spring holds its own monitor there.

Critical Safety Warning: Loosening a pole collar can let an arm and its monitor slide down the pole at once. Changing spring tension can make an arm rise or sink on its own, and an empty spring arm can spring up hard.

These happen when collars or tension screws are adjusted without supporting the load.

• Hold the arm and monitor from below before loosening any collar on the pole.
• Keep a hand under the monitor while turning a tension screw.
• If a monitor must come off, put its arm in the removal position its instructions specify, and don't pull the empty arm down by hand.

Step 1 - Measure Both Screens and Pick the Shared Edge

Measure with both monitors on and in place. Take each measurement straight up from the desk surface to the edge of the lit picture, not the frame.

1. Measure the tops: Note the height of each screen's top picture edge.
2. Measure the centers too: Halfway between each screen's top and bottom picture edges.
3. Identify your arm type: Check whether each side moves up and down on its own, whether each arm attaches to the pole with its own collar, or whether both screens hang from one fixed bar.

Then choose which edge to share:

• Tops (usual choice): Your eyes start from the top of most windows, so a shared top line keeps them level as you look across. The larger screen then extends lower.
• Centers: Use this if matching tops would push the larger screen's bottom into the desk, keyboard, or speakers.

Pick the line's height from where your main screen sits. How High Should a Monitor Be Relative to Eye Level? explains how to measure that starting height. If one screen is in portrait, follow the portrait-and-landscape alignment method instead, since the shared edge works differently.

Independent spring arms: go to Fix A. Arms with their own collars, or arms without vertical movement: go to Fix B. One fixed bar: go to Fix C.

Step 2 - Bring Each Screen to the Line

All three fixes use the dual arm's assembly guide. Find the model name on the label under the arm or on the clamp base, then check the guide for each side's weight range, where the tension screws are, and how the collars or plates adjust.

Put a strip of painter's tape on the wall or a vertical surface behind the screens at your chosen line before you start.

Fix A - Set Each Spring Arm Separately

Use when: Each side of the dual arm moves up and down on its own spring.

Before you start: Hold the monitor on the side you are tuning, because a tension change can make that arm start moving under your hand. See why tension changes move the arm.

You need: Each monitor's weight without its stand, from its spec sheet. Each must fall inside that side's stated range.

1. Set the main screen first: Bring its chosen edge to the tape.
2. Tune that side's tension: If it rises or sinks after release, adjust that side's tension screw a half turn at a time until it holds.
3. Set the second screen: Bring its matching edge to the same tape.
4. Tune the second side on its own: Its tension may end up very different from the first side's. That's expected with different monitors.
5. Close the inner gap: Bring the inner edges close without letting the frames rub.

Check: Both edges sit on the tape and each screen stays there after release. Go to Step 3 to confirm. If one arm hits the top or bottom of its travel before reaching the tape, use Fix B.

Fix B - Shift One Arm on the Pole

Use when: Each arm clamps to the pole with its own collar, and one arm can't reach the line by its own movement, or the arms don't move vertically.

Before you start: Support the arm and its monitor from below before loosening its collar, or both can drop down the pole together. Read the collar precaution.

You need: The difference between the two screens' chosen edges from Step 1. That is how far one arm needs to move.

1. Pick the arm to move: Usually the side screen, so your main screen stays where it is.
2. Mark its current position: Put tape on the pole at the collar's edge.
3. Support and loosen: Hold the arm under its collar and loosen the collar just enough to slide.
4. Slide by the measured difference: Move up or down using the pole tape as your reference.
5. Tighten fully before letting go: Tighten it as the guide directs, then release the arm slowly.

Check: The collar holds and both edges sit on the tape. Go to Step 3. If the arms swing into each other at the new height, move the collar a little and recheck the swing.

Fix C - Work With a Fixed Bar Mount

Use when: Both monitors hang from one horizontal bar, and neither side can move up or down separately.

Before you start: Changing a mounting plate means taking a monitor off the bar, so have a helper hold the screen until every screw is in. Review the handling precautions.

1. Check for adjustable plates: Some bar mounts let each VESA plate sit at more than one height. The guide shows whether yours does.
2. Consider a VESA adapter plate: A plate that shifts the mounting point up or down can raise or lower one screen. It must list your VESA pattern and a weight rating above that monitor's weight.
3. Watch the added leverage: An offset plate moves the screen's weight away from the bar. Check that the bar doesn't twist or tilt afterward.
4. Replace the mount if neither works: A dual arm with independent height on each side is the dependable fix for mismatched monitors.

Check: Both edges sit on the tape and the bar sits level. Go to Step 3 for the final check.

Step 3 - Check the Tops Stay Level

Sit in your normal position and look across both screens. Then leave them for an hour of normal use and check the tape again.

PASS: Both chosen edges sit on the tape after an hour, your eyes move straight across, every collar and plate holds, and the screens don't touch when you move them.

FAIL: One screen has moved off the line, a collar has slipped, or the screens rub when you adjust them.

NEXT ACTION:

• The heavier screen slowly sinks: Add tension to that side only with Fix A. If it sinks at full tension, see Why Does My Monitor Arm Keep Falling Down?
• The lighter screen keeps rising: Reduce that side's tension. If it rises at minimum, see Monitor Arm Won't Stay Down With a Light Monitor.
• A collar slipped: Support the arm, reset it to the pole tape, and retighten with Fix B. If it slips again at full tightness, stop using that collar and replace it.
• The screens rub: Open the inner gap slightly, or angle the side screen in a little more.

Common Mistakes

Mistake: Setting both arms to the same tension because they are the same model.

What happens: The heavier monitor sinks and the lighter one rises, undoing the alignment within hours.

Instead: Tune each side to its own monitor's weight.

Mistake: Lining up the mounting plates or the frames.

What happens: The pictures stay offset, because the monitors differ in size, bezel, and VESA position.

Instead: Measure and match the lit picture edges.

FAQ

Can I put a much heavier monitor on one side of a dual arm?

Only if each monitor falls inside its own side's weight range and the whole mount's total limit. A very uneven pair also loads the clamp more on one side.

Should I match the display settings too?

Yes. Drag the screen icons in your computer's display arrangement to match the physical line, so the pointer crosses without jumping.

This guide covers two landscape monitors of different sizes or models on one dual mount. The aligned height is a physical starting position; adjust it to your own comfortable viewing posture.

Written and edited by Lio Lim

Every guide on The ErgoDesk Lab is reviewed before it goes live so each step leads to a clear next action. Spotted something unclear or wrong? Let us know, or read how these guides are made.