A 27-inch screen measure 68.6 cm diagonal. Screen size is always measured in diagonal, as specified by manufacturers in inches (1 inch = 2.54 cm). Below you'll find the inches to centimeters conversion table A complete guide, plus tips on choosing the right size based on your needs.
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Screen Size Chart (inches / cm)
To convert a diagonal in inches in centimeters, you simply multiply by 2,54. The table below covers all common sizes, from smartphones to large TVs, with the width x height and the slab surface for each model.
| Screen type | Diagonal in inches | Diagonal in cm | Format | Width x Height (cm) | Surface area (cm²) |
|---|---|---|---|---|---|
| Telephone | 3,5″ | 8.9 cm | 16/9 | 7.7 x 4.4 cm | 33.8 cm2 |
| Telephone | 3,5″ | 7.5 cm | 16/10 | 7.5 x 4.7 cm | 35.5 cm2 |
| Telephone | 4″ | 10.2 cm | 16/9 | 8.9 x 5 cm | 44.1 cm² (1.2 in²) |
| Telephone | 5″ | 12.7 cm | 16/9 | 11.1 x 6.2 cm | 68.9 cm2 |
| Telephone | 6″ | 15.2 cm | 16/9 | 13.3 x 7.5 cm | 99.2 cm2 |
| Tablet | 7″ | 17.8 cm | 16/9 | 15.5 x 8.7 cm | 135.1 cm² of surface area |
| Tablet | 8″ | 20.3 cm | 16/9 | 17.7 x 10 cm | 176.4 cm² of surface area |
| Tablet | 9″ | 22.9 cm | 16/9 | 19.9 x 11.2 cm | 223.3 cm² (8.5 in²) |
| Computer | 10″ | 25.4 cm | 16/9 | 22.1 x 12.5 cm | 275.7 cm² (7.8 in²) |
| Computer | 12″ | 30.5 cm | 16/9 | 26.6 x 14.9 cm | 397 cm² surface area |
| Computer | 14″ | 35.6 cm | 16/9 | 31 x 17.4 cm | 540.3 cm2 |
| Computer | 15″ | 38.1 cm | 16/9 | 33.2 x 18.7 cm | 620.3 cm² of surface area |
| Computer | 17″ | 43.2 cm | 16/9 | 37.6 x 21.2 cm | 796.7 cm2 |
| Monitor / TV | 19″ | 48.3 cm | 16/9 | 42.1 x 23.7 cm | 995.2 cm2 |
| Monitor / TV | 22″ | 55.9 cm | 16/9 | 48.7 x 27.4 cm | 1334.3 cm² surface area |
| Monitor / TV | 24″ | 61 cm | 16/9 | 53.1 x 29.9 cm | 1,587.9 cm² (1,587.9 sq. in.) |
| Monitor / TV | 27″ | 68.6 cm | 16/9 | 59.8 x 33.5 cm | 2003.3 cm² |
| Monitor / TV | 28″ | 71.1 cm | 16/9 | 62 x 34.9 cm | 2161.3 cm² of surface area |
| Monitor / TV | 30″ | 76.2 cm | 16/9 | 66.4 x 37.4 cm | 2481.1 cm² of surface area |
| Monitor / TV | 32″ | 81.3 cm | 16/9 | 70.8 x 39.8 cm | 2822.9 cm² surface area |
| Television | 40″ | 101.6 cm | 16/9 | 88.6 x 49.8 cm | 4,411.4 cm² |
| Television | 43″ | 109.2 cm | 16/9 | 95.2 x 53.5 cm | 5,093.2 cm² |
| Television | 50″ | 127 cm | 16/9 | 110.7 x 62.3 cm | 6,896.6 cm² |
| Television | 55″ | 139.7 cm | 16/9 | 121.8 x 68.5 cm | 8,343.3 cm² |
| Television | 65″ | 165.1 cm | 16/9 | 143.9 x 80.9 cm | 11,641.5 cm² |
| Television | 75″ | 190.5 cm | 16/9 | 166 x 93.4 cm | 15,504.4 cm² |
| Television | 85″ | 215.9 cm | 16/9 | 188.2 x 105.8 cm | 19,911.6 cm² |
Please note: the display area The actual size is always slightly smaller than the finished product. The borders around the slab add a few centimeters to the frame. Be sure to check the overall dimensions the TV before deciding where to place it.
How do you measure a screen?
To find out the size of a screen, you always measure its diagonal, that is, the distance from one corner to the other of the slab. A simple ruler placed diagonally will give you the measurement in centimeters. Manufacturers express this value in inches, since’1 inch is equal to 2.54 cm.
But the diagonal doesn't tell the whole story. The format (or aspect ratio) determines the width and the height actual screen dimensions. A format 16/9 means that the aspect ratio is 16:9: this is the standard for video and most computer and televisions. For screens of the same diagonal length, two screens of different aspect ratios therefore do not display the same usable area.
Here is a concrete example involving two tiles advertised at 3.5 inches :
- Format 16/9 : 8.9 cm diagonal, 7.7 cm wide, 4.4 cm high, or 33.8 cm2.
- Format 16/10 : 7.5 cm diagonal, 7.5 cm wide, 4.7 cm high, or 35.5 cm2 (such as the iPhone 3 and iPhone 4).
Also, be aware of manufacturers' rounding. A screen sold for 17 inches actually ranges between 41 and 44 cm display diagonal. Finally, the frame and the stand add a few centimeters to the overall dimensions, so be sure to check this before installing a large TV.
Calculate the dimensions yourself (formula)
The diagonal The given side is the hypotenuse of a right triangle. Using the Pythagorean theorem, you can find the width (l) and the height (h) starting from the diagonal (d) and the format :
- Format 4/3 : h = 3 × d / 5 and l = 4 × d / 5
- Format 16/9 : h ≈ d / 2 and l ≈ 8 × d / 9
- Format 16/10 : h = 10 × d / √356 and l = 16 × d / √356
The surface The area of the slab(s) is then calculated as s = l × h.
What screen size should you choose based on your usage?
The ideal size depends on what you're doing on the screen and on the distance depending on where you sit. A screen that's too big when viewed from too close a distance strains your eyes. Here are some practical guidelines based on usage:
- Office PC : 24 to 27 inches (61 to 68.6 cm). Wide enough to open multiple windows side by side without taking up too much desk space. For intensive use (video editing, graphic design), it can be expanded to 27 to 32 inches.
- Competitive Gaming (FPS, esports): the 24-inch size It remains the gold standard. At close range, you can take in the entire screen at a glance, which improves responsiveness.
- Immersive Gaming : aims to 27 inches in resolution 1440p, the best balance of comfort and immersion.
- Laptop : a slab of 15 to 16 inches (38 to 40 cm) strikes a balance between readability and portability. For lightweight portability, a 14 inches That's enough.
- Tablet : THE 10- to 11-inch size covers everyday use (reading, watching videos, browsing the web).
- Living Room TV to about 2.5 m rear sight: aims 65 to 75 inches (165 to 190 cm diagonal). Below 2 m, a 55 inches It's going very well.
Simple rule: the farther you are from the screen, the bigger the image you can see. And the more the diagonal the more it increases, the more a good resolution in pixels is important for maintaining a sharp image.
To play anywhere, you can also choose a portable screen like the Portable Gaming Monitor Arzopa, compact and easy to carry.
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Inches Instead of Centimeters: Why?
The human body has long served as a reference for units of measurement. The thumb, foot, and hand provided practical but approximate benchmarks, and their values varied from country to country. This unit of measure comes mainly from the United States and the tech industry, which has retained it for the screen diagonal.
Since 1959, an international agreement established the conversion once and for all: 1 inch = 2.54 cm, all over the world. That’s why your screen size is still measured in inches, even in France. To connect your screen properly, it’s also worth understanding the differences between DisplayPort vs. HDMI before choosing your cable.
If you have a OLED screen, and be sure to maintain it properly to preserve its image quality over time.
And to compare the latest models, take a look at the best-selling screens in France:
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