Flat is not equidistant
Put two 27 inch panels side by side on a straight desk with your eye 26 inches from the middle of the array, and the centre of each panel is 28.73 inches away, not 26. That is 2.73 inches further, about ten and a half percent, and it is entirely a consequence of laying a wide object across a line when the eye is a point in front of it.
The bigger effect is angular. Each panel faces straight forward while sitting 12.23 inches off to the side, so it is presenting its face to a point past your shoulder. Turning it 25.18 degrees squares it to your eye. That angle is not a preference; it is where the panel centre happens to be relative to where you are.
Toeing in costs depth, and buys width back
Rotating a panel about its own centre swings half of it backwards and half of it forwards. The width it occupies shrinks by the cosine of the angle and the depth it occupies grows by the sine. At the defaults, two 24.2 inch units toed in 25.18 degrees occupy 44.05 inches instead of 48.65 — 4.6 inches narrower — while the swing adds 10.3 inches of depth on top of whatever the stand feet need.
| Turn | Width of one 24.2 in unit | Depth it swings through |
|---|---|---|
| 0° | 24.20 in | 0.00 in |
| 10° | 23.83 in | 4.20 in |
| 20° | 22.74 in | 8.28 in |
| 30° | 20.96 in | 12.10 in |
| 45° | 17.11 in | 17.11 in |
That table is why depth runs out before width does on a normal desk. A 30 inch desk with 8 inches of stand foot behind the glass has 22 inches left, and past about 40 degrees of toe-in a 24 inch panel has eaten it.
The arc is a different animal
A true arc puts every panel centre at the same distance from your eye, which means the panels are chords of a circle whose radius is that distance. It is the layout that removes the distance difference entirely, and it is far more aggressive than people expect, because the arc length has to equal the total panel width.
Two 24.2 inch units on a 26 inch radius sweep 111.49 degrees between them. End to end they measure 42.98 inches across, and the outer panels come 11.37 inches forward of the middle one. Add a third panel at the same radius and the sweep reaches 167.51 degrees, with the outer panels 23.17 inches forward — the array has wrapped most of the way around your head, and the calculator says so rather than printing a width that looks reasonable.
The gap you set is not the gap you get
Panels turned toward you close on each other at the join, because the inner edge of each swings backwards while the neighbouring outer edge swings forward. The gap entered here is the gap with the panels square to the desk. Set the angle first and then measure what is left between the frames; on a tight setup the frames can touch before the angle is where you wanted it.
What holds them up
A multi-panel array is a lot of weight cantilevered over a desk, and most of the ways it fails are mechanical rather than geometric: a clamp on a thin desk edge, a pole base that a turned panel loads off-centre, a fixing into plasterboard with nothing behind it. Naming those is as far as this page goes. What size fastener holds what is a question for the hardware and the surface it is going into.
Questions people ask
How much should I angle my monitors?
The calculator gives you one specific angle and it is not a recommendation: it is the angle at which each panel is square to the line from your eye to that panel centre, given the width, the gap and the distance you entered. Whether you want the panels square to your sight line is a separate question that depends on what is reflected in them and how you use the outer screens, and this page has no view on it. If you angle less than the figure, the outer panels are still turned partly away; if you angle more, they are turned past you.
Why does the arc option sometimes say the geometry is impossible?
Because a panel is a straight object and an arc of a given radius can only accommodate so much straight length before it closes on itself. Each panel is a chord of a circle whose radius is your viewing distance, and if the panel is wider than the circle across, there is no chord. Even short of that, three wide panels at a short viewing distance sweep past 180 degrees, at which point the array has curled around behind your eyes and the numbers stop describing a thing you could build. The page reports the sweep angle so you can see it happening rather than trusting a width figure that quietly stopped meaning anything.
Do bezels matter that much?
They matter twice over. Each panel carries a frame on both sides, so two panels put four frame widths into the array before any gap. At 0.35 inches a side that is 1.4 inches, and on an older monitor with a half inch frame it is two. Separately, the frame is what limits how close the glass edges can come at the join once the panels are turned, because the frames meet before the glass does. The width figures on this page are all glass plus frame for exactly that reason.
Is a curved panel the same as an arced array?
It solves the same problem at a different scale and the two are independent. A curved panel bends a single screen so its own edges are closer to the equidistant condition, described by a radius quoted in millimetres. An arced array turns whole panels relative to each other. You can have both, in which case the curve handles the within-panel geometry and the toe-in handles the between-panel geometry, and this calculator is only doing the second. Enter the flat width of the curved panel and be aware the result will be slightly conservative.
What desk depth does a three-panel setup actually need?
It depends almost entirely on the angle, and the calculator will show it for your numbers. As a shape of the answer: the depth is the stand foot reach behind the glass plus the panel width times the sine of the turn angle. A 24 inch unit turned 30 degrees swings through 12 inches, so with 8 inches of stand foot the array wants 20 inches of the desk before anything else is on it. That is why three-panel setups so often end up on arms clamped behind the desk rather than on their own feet.