This monitor size calculator turns a screen's diagonal and aspect ratio into its real width, height and area, in inches or centimeters, and draws two screens side by side to the same scale. Compare a 24 inch with a 27 inch, a 27 inch 16:9 with a 34 inch ultrawide, or a 55 inch TV with a 65 inch. It also works out how wide a curved monitor is on your desk and how far its edges come forward, the pixel density when you add a resolution, and the 16:9 size that has the same height as an ultrawide. It works as a screen size calculator and monitor dimensions calculator for laptops, tablets and TVs too.
How to use the monitor size calculator
- Press one of the Compare buttons for a common pair, or set each screen yourself.
- For each screen, type the diagonal and choose the aspect ratio. Ultrawides are listed by their real resolution, because "21:9" covers three different shapes.
- Optionally pick the resolution, to see pixel density, and the curve, to see the desk width of a curved screen.
- Switch between Side by side and Overlaid to see the difference in width and height.
- Read the comparison under the drawing and the full table below it. Copy results gives you a text version.
What the results mean
| Result | What it tells you | 27 in 16:9 vs 34 in ultrawide |
|---|---|---|
| Screen area | How much bigger or smaller B's picture is | +32% |
| Width | Difference in width as seen from the front | +7.6 in, +19.2 cm |
| Height | Difference in picture height | -0.1 in, almost the same |
| B is as tall as | The 16:9 screen size with the same height as B | 26.8 in |
| Width on the desk | Straight line width of a curved screen | 31.1 in at 1800R |
| Depth of the curve | How far the edges come toward you | 1.7 in, 4.4 cm at 1800R |
| Pixel density | Sharpness, when a resolution is set | 108.8 vs 109.7 PPI |
How monitor size is worked out
The size on the box is the diagonal of the visible picture. With the aspect ratio you can get the rest:
- Width = diagonal × ratio width ÷ √(ratio width² + ratio height²)
- Height = diagonal × ratio height ÷ √(ratio width² + ratio height²)
For a 27 inch 16:9 screen, √(16² + 9²) = 18.36, so the width is 27 × 16 ÷ 18.36 = 23.5 inches and the height 27 × 9 ÷ 18.36 = 13.2 inches. The frame, the stand and any chin under the screen come on top of that.
Common monitor and TV sizes
| Screen | Picture width × height | In centimeters |
|---|---|---|
| 24 in 16:9 | 20.9 × 11.8 in | 53.1 × 29.9 cm |
| 27 in 16:9 | 23.5 × 13.2 in | 59.8 × 33.6 cm |
| 32 in 16:9 | 27.9 × 15.7 in | 70.8 × 39.8 cm |
| 34 in ultrawide, 3440 × 1440 | 31.4 × 13.1 in | 79.7 × 33.3 cm |
| 38 in ultrawide, 3840 × 1600 | 35.1 × 14.6 in | 89.1 × 37.1 cm |
| 49 in super ultrawide, 32:9 | 47.2 × 13.3 in | 119.8 × 33.7 cm |
| 55 in TV, 16:9 | 47.9 × 27.0 in | 121.8 × 68.5 cm |
| 65 in TV, 16:9 | 56.7 × 31.9 in | 143.9 × 80.9 cm |
Going from 24 to 27 inches adds about 27% more screen area, which is why the step feels larger than three inches suggests.
Ultrawide or 16:9?
Diagonal sizes mislead when the shapes differ. A 34 inch ultrawide sounds much bigger than a 27 inch monitor, but it is the same height and simply wider. The B is as tall as readout makes this clear:
- A 34 inch 3440 × 1440 ultrawide is as tall as a 26.8 inch 16:9 screen.
- A 38 inch 3840 × 1600 ultrawide is as tall as a 29.8 inch 16:9 screen.
- A 49 inch 32:9 super ultrawide is as tall as a 27.1 inch 16:9 screen, the size of two 27 inch monitors side by side.
If text on your current 27 inch 1440p monitor is a comfortable size, a 34 inch 3440 × 1440 or a 49 inch 5120 × 1440 shows it at the same size, because the pixel density is the same. The ppi calculator shows the density of any other pairing.
Curved monitors on a desk
Curved screens are measured along the curve. The rating gives the radius in millimeters, so 1800R is part of a circle 1.8 meters in radius. Because of the curve, the screen is a little narrower on your desk than its picture width, and the edges stand forward of the middle. A 34 inch ultrawide at 1800R takes 79.0 cm of desk width instead of 79.7 cm, and its edges come forward 4.4 cm. A 49 inch at 1800R is 117.6 cm wide on the desk and nearly 10 cm deep from edge to middle, which matters on a shallow desk or with a monitor arm.
How far to sit from a TV
For TVs, a common cinema recommendation is a screen that fills 30 to 40 degrees of your view. For a 55 inch TV that means sitting 1.7 to 2.3 meters away, and for a 65 inch, 2.0 to 2.7 meters. If you sit further back than that, a bigger screen is worth it. For sharpness at a given distance, check the pixel density with the ppi calculator.
Measuring your own screen
Measure the visible picture diagonally from corner to corner, not including the frame. On a laptop the model number on the label underneath leads to the exact size on the maker's site. Many TVs are sold by class, so a 65 inch class TV may measure 64.5 inches. To check what resolution your screen is running at, use the what is my screen resolution page, and to see how a ratio fits a screen, the aspect ratio calculator.
What a monitor size calculator cannot tell you
The calculator measures the picture, not the whole monitor. Frames, stands and chins differ between models, so check the maker's dimensions for desk and arm planning. It assumes the stated diagonal and ratio are exact, and treats a curved screen as part of a perfect circle. Size also says nothing about picture quality: once you have chosen, the monitor test checks the new screen for dead pixels, uniformity and color.
Monitor size questions
How wide is a 27 inch monitor?
A 27 inch 16:9 monitor has a picture 23.5 inches wide and 13.2 inches high, or 59.8 × 33.6 cm. The frame adds from a few millimeters to about 2 cm on each side, so check the maker's dimensions before buying a desk or a monitor arm.
Is a 34 inch ultrawide bigger than a 27 inch monitor?
Yes, it has about 32% more screen area and is about 20 cm wider, but it is almost exactly the same height. A 34 inch 3440 × 1440 ultrawide is like a 27 inch 1440p monitor with an extra strip added to each side, at the same pixel density.
How do you measure monitor size?
Measure the visible picture diagonally, from one corner to the opposite corner, without the frame. Makers quote that diagonal in inches. On a curved screen it is measured along the curve.
What does 1800R mean on a curved monitor?
The curve follows a circle with a radius of 1800 mm, or 1.8 meters. A smaller number means a tighter curve: 1000R is very curved, 3800R is gentle. Set the curve in the calculator to see how much narrower the screen is on your desk and how far the edges come forward.
What size monitor equals two 27 inch screens?
A 49 inch 32:9 super ultrawide. At 5120 × 1440 it has the height and pixel density of a 27 inch 1440p monitor and the width of two of them side by side, without the frames in the middle.
How big is a 32 inch monitor in centimeters?
A 32 inch 16:9 screen is 70.8 cm wide and 39.8 cm high, with a diagonal of 81.3 cm. That is 27.9 × 15.7 inches.