Begin with actual housing widths
Find the outside width of each monitor in its specification sheet. Add both widths and the gap you want between them. Compare that total with your clear desktop width. Screen diagonals alone are not enough: a diagonal measures a different line through the screen.
Our desk-fit calculator estimates panel widths when you do not have the models yet. Its bezel allowance is an input you can change. Replace the estimates with the real dimensions before ordering.
Work through a 48-inch example
Two hypothetical housings measuring 24.2 inches each, with a 0.5-inch gap, span 48.9 inches when placed in a straight line. On a 48-inch desk, that is 0.9 inches wider than the surface. That comparison says nothing about whether overhang is safe or convenient. Check walls, doorways, and how each display is supported.
Turning the screens inward can reduce their front-facing span but increases the depth the arrangement occupies. A portrait secondary screen changes the width budget too. Check the mount's rotation and the monitor's permitted orientation before planning around it.
Choose the mount after the layout
Draw the two screen positions first. Then locate the mounting points and ask whether the arms can reach those positions without colliding with each other or the wall. Measure each screen's weight without its original stand. Both must meet the mount's individual limits.
A dual arm can consolidate the base, but it does not make two wide displays narrow. If the task only occasionally needs a second display, compare an open laptop beside one monitor with a permanent two-monitor arrangement. Choose the setup that supports your actual work.
Compare relevant options
These links open our sourced shortlist. Check the complete limitations before choosing.
About this guide
Worked examples are illustrative calculations, not measurements from product testing. Follow the instructions for your exact equipment. Read our research and correction policy.