DeviceBenchFree monitor size comparison
Two monitors, drawn over each other to scale
Enter two diagonals and two shapes and both screens appear as outlines at a single scale, bottom edges on the same line the way they would stand on a desk, with their real widths, heights and viewing areas underneath in inches and centimeters. That is the arrangement that exposes what a diagonal hides: a 34-inch ultrawide is 7.83 inches wider than a 27-inch 16:9 and about a tenth of an inch shorter, and a 32-inch panel has 40% more glass than a 27-inch one rather than the 19% its diagonal suggests. Nothing here is measured from your hardware — it is geometry on the two sizes you type.
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- No signup
- Both drawn to scale
- Inches and centimeters
- Nine real ratios
Screen one
Screen two
Both outlines are the visible glass only, drawn at one scale with their bottom edges on the same line — the way two monitors sit on the same desk. Bezels and stands are not included.
Screen one — 27.0 in at 16:9
- Width
- 23.53 in · 59.8 cm
- Height
- 13.24 in · 33.6 cm
- Viewing area
- 312 sq in · 2010 cm²
- Shape
- 1.778 : 1
Screen two — 34.0 in at 43:18
- Width
- 31.36 in · 79.7 cm
- Height
- 13.13 in · 33.3 cm
- Viewing area
- 412 sq in · 2656 cm²
- Shape
- 2.389 : 1
Five lines, which is what a message to whoever is buying the second monitor needs.
Add the frame back before you trust a desk measurement: a modern three-side-borderless panel adds roughly 6 to 10 mm at the sides and 15 to 25 mm along the bottom chin, and the stand is usually the widest part of the whole assembly. A monitor arm removes the stand from the arithmetic entirely, which is often the difference between two panels fitting side by side and not.
How to compare two monitor sizes
Two descriptions in, three differences out. The differences are the part worth reading.
Describe the screen you have now
Put its diagonal in the first box and pick its shape underneath. The list names each ratio by what the panel actually measures rather than by what the marketing says, so a 3440 × 1440 ultrawide appears as 43:18 and a 2560 × 1080 one as 64:27 — a distinction that changes the height figure by more than a tenth of an inch.
Describe the one you are considering
Fill the second box the same way. The drawing redraws on every keystroke with the larger of the two panels behind, so the smaller outline is never hidden and you can see at a glance where the extra glass is going — sideways, upwards, or both.
Read the three differences, not the two diagonals
Underneath the drawing sit the only numbers that decide anything: how much wider the second screen is, how much taller or shorter, and how much more viewing area it has as a percentage. Width tells you whether it fits the desk, height tells you how many lines of text you keep, and area is the one that tracks what you are paying for.
Technical specifications
| Width formula | diagonal × a ÷ √(a² + b²), with a and b swapped for the height; the two multiplied give the viewing area |
|---|---|
| The pairing the page opens on | 27 in at 16:9 is 23.53 × 13.24 in; 34 in at 43:18 is 31.36 × 13.13 in — 7.83 in wider and 0.11 in shorter |
| Area against diagonal | Area follows the square of the diagonal at a fixed shape: 32 in beside 27 in is 19% more diagonal and 40% more glass |
| Height cost of going ultrawide | At an unchanged 27-inch diagonal, 43:18 gives up 2.81 in of height against 16:9 — a 21% loss |
| Shape presets | Nine, named as the panel measures rather than as it is advertised: 3440 × 1440 appears as 43:18, not 21:9 |
| How the two are stacked | Bottom edges on one line and centers aligned, the way two monitors stand on a desk; the larger area is drawn behind |
| Input accepted | Diagonals above 0 and up to 200 inches, typed in inches or centimeters, plus any custom ratio of two positive numbers |
| Deliberately not compared | Pixel density, panel technology, refresh rate and bezel width — the outlines are lit glass and nothing else |
Frequently asked questions
Is a 34-inch ultrawide bigger than a 27-inch 16:9?
Wider and larger in area, but very slightly shorter, which is the answer that surprises people. A 34-inch panel at the true 43:18 shape of a 3440 × 1440 screen measures 31.36 by 13.13 inches; a 27-inch 16:9 measures 23.53 by 13.24 inches. So you gain 7.83 inches of width and 32% more glass, and you lose about a tenth of an inch of height — meaning a document, a code file or a web page shows exactly as many lines as before, side by side with a second one.
Why is a 32-inch monitor so much larger than a 27-inch when the diagonal grew by five inches?
Because area grows with the square of the diagonal, so a 19% longer diagonal is 40% more glass at the same shape. That squaring is why the step from 24 to 27 inches feels modest and the step from 27 to 32 feels like a different piece of furniture, and it is also why the price gap between sizes widens faster than the inch count does. The percentage under the drawing is the figure to compare, not the difference in diagonals.
Two screens have the same diagonal but different shapes. Which one is taller?
The one closer to square, always, and by more than people expect. Hold the diagonal at 27 inches and a 16:9 panel is 13.24 inches tall while a 43:18 ultrawide is 10.43 — a loss of 2.81 inches, or 21% of the vertical space, for the same nominal size. It is the reason ultrawide buyers usually go up two or three inches of diagonal at the same time: at 34 inches the ultrawide has clawed the height back to roughly where a 27-inch 16:9 started.
Is a monitor sold as 21:9 actually 21:9?
No, and neither of the two common panels is. A 3440 × 1440 screen is 43:18, or 2.389:1, and a 2560 × 1080 screen is 64:27, or 2.370:1; 21:9 is 2.333:1 and describes neither. The gap looks trivial and is not: at a 34-inch diagonal, calculating with 21:9 instead of 43:18 overstates the height by a quarter of an inch and understates the width by a tenth of one. Both real ratios are in the shape list here for that reason.
Will a 34-inch monitor fit on my desk?
Measure the width from the drawing and then add the hardware, because the glass is never the widest part. A modern thin-bezel panel adds roughly 6 to 10 millimeters of frame at each side, and the stand — especially a wide-footed or forward-arching one — usually sets the real footprint and can add 5 to 15 centimeters of depth. A VESA arm takes the stand out of the arithmetic entirely and is often what makes two monitors sit side by side where they otherwise would not.
Does a wider monitor show more of the game?
It does, but only if the game is told to render a wider field of view, and not every game will. Titles with proper ultrawide support extend the horizontal field and keep the vertical one, which is genuinely more scene on screen; titles without it letterbox the image or, worse, crop the vertical field so that a wider display shows less than a 16:9 one. Competitive shooters sometimes lock the field of view on purpose, so it is worth checking a specific game before buying a shape for it.
Why is the diagonal the number on the box at all?
It is inherited from television, where cathode-ray tubes were round-cornered and the diagonal was the only dimension that described the tube regardless of how much of it was masked off. It survived because it is one number instead of two, and it is a flattering one — it grows more slowly than area, so a modest-sounding increase hides a large one. On flat panels the quoted diagonal is at least honest about the visible picture, which was not always true of CRTs sold as 19-inch with 18 inches of usable glass.
About diagonals, aspect ratios and the arithmetic behind both
A diagonal on its own describes no rectangle. Any number of shapes share it, and the width and height only fall out once you also know the ratio: for a screen of diagonal D and shape a:b, the width is D × a ÷ √(a² + b²) and the height is D × b ÷ √(a² + b²). Multiply those and the viewing area comes to D² × a × b ÷ (a² + b²), which carries two consequences that catch buyers out. The first is the D² — at a fixed shape, area grows with the square of the diagonal, so a 19% larger number on the box is 40% more glass in front of you. The second is the a and b in the numerator: for a fixed diagonal, area falls as the rectangle gets more elongated, which means a 27-inch ultrawide is not a bigger 27-inch monitor but a smaller one stretched sideways.
The default pairing on this page is the comparison people actually come here for, and it is worth spelling out because the drawing makes it obvious and the specifications never do. A 3440 × 1440 ultrawide sold as 34-inch has the shape 43:18, not the 21:9 it is marketed as, which puts it at 31.36 by 13.13 inches. A 27-inch 16:9 is 23.53 by 13.24. So the ultrawide is 7.83 inches wider, 32% larger in area, and about 2.7 millimeters shorter — a rounding error vertically, and a second full document horizontally. That is a genuinely different trade from the one the diagonals imply, and it is why the height row here is worth more attention than the diagonal difference. It also has a cost the outlines cannot show: those extra pixels have to be drawn, and 3440 × 1440 is 34% more of them than 2560 × 1440, which is the sort of change that shows up as a lower reading on an in-browser frame rate test long before it shows up in a game.
Two things this page deliberately leaves alone. Pixel density is not compared here, because two panels of the same physical size can differ by a factor of two in sharpness and the answer belongs to the density calculator, where the pixel grid is an input rather than an assumption. And field of view is a game setting rather than a property of the glass: a wider screen only shows more scene if the engine is asked to extend the horizontal field, which is what the fov calculator converts between when you move from one shape to another. If you want to sanity-check any of the outlines against the monitor already in front of you, the calibrated on-screen ruler will measure the real width of your current panel in about a minute — which is also the fastest way to catch a listing that quoted a diagonal it should not have.
What the comparison knows about you
Every number on this page is worked out by JavaScript running in the tab you are reading it in. Nothing you type, paste or open is uploaded, logged or kept, which is also why the tools carry on working after you disconnect from the network.
Less than any other page in this section, as it happens: this one never reads your display at all. Two diagonals and two ratios are typed in, the geometry is done in the tab, and closing it takes the whole comparison with it — there is no history of which monitors you were weighing up and nothing written to this browser to build one from.