Screen Size
Screen Size — runs in your browser. Inputs are not stored.
Screen size (diagonal → width & height)
Enter values, then press Calculate.
How to use
- Enter the labeled inches of a monitor or TV in Diagonal (inches). The default sample is 27.
- In Ratio, pick 16:9, 16:10, 21:9, 4:3, or 32:9, or choose custom.
- For custom, enter Width ratio and Height ratio. Defaults are 16 and 9.
- Press Calculate to see width and height in cm. 1 inch = 2.54 cm; sides are split with Pythagoras.
- Bezel and OSD exaggeration are omitted. This is an approximation of the panel’s active area. Millimetres are shown only as cm.
Key concepts
The screen size calculator is for monitor width, the real size of a 27-inch 16:9 panel, and desk layout. With diagonal and aspect ratio, width = diagonal × width-ratio / √(width-ratio² + height-ratio²). It turns diagonal inches and aspect ratio into width and height in cm for desk planning. The bezel is omitted. PPI is omitted. Use it to compare desk width with monitor width in cm; stand and bezel are left out of the active-area approximation. The same inch size yields different width and height when the aspect ratio changes.
Resolution (pixels) and PPI are not calculated. If you have inches but the ratio is wrong, the side lengths go off. Calculation is local. 1 inch = 2.54 cm. Custom ratio also allows 3:2 and 5:4. Sides are split with Pythagoras.
Example
27-inch 16:9 is about 59.8 cm wide and 33.6 cm tall. 24-inch 16:9 is about 53.1 cm wide. 32-inch 21:9 is longer and shorter than the same diagonal at 16:9. Compare with your desk width. 32-inch 16:9 is about 70.8 × 39.8 cm. 34-inch 21:9 feels shorter and wider. A 14-inch 16:9 laptop is about 31.0 × 17.4 cm. 16:10 is a little taller.
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Frequently asked questions
Does screen size include the bezel?
It approximates the panel’s active area. Add the stand and bezel separately. Stand width is not included.
Is the diagonal sent to a server?
No. You still need a ratio to split the sides. Inches alone cannot split width and height.
Can I enter a custom aspect ratio?
Choose custom in Ratio to open width-ratio and height-ratio fields. Ratios such as 3:2 work there.
If I only know inches, do I get width and height?
A ratio is required to split width and height. Inches alone give only the diagonal physical length—the hypotenuse.
Are results also shown in mm?
They are shown in cm. Multiply by 10 for mm.
Does it also calculate PPI from resolution?
This tool only finds physical size. Pixel counts are not entered, so there is no PPI.
Last reviewed: 2026-09-04