Screen Size and PPI Calculator
Turn a diagonal measurement into actual width and height.
Your numbers
Your results
Width (in)
Width (in)
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Height (in)
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Width × height (cm)
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Screen area (sq in)
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Pixel density (PPI)
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Screen Size and PPI Calculator by TheCalcTools
How the Screen Size and PPI Calculator works
Enter the diagonal size and the aspect ratio, for example 16:9.
Width and height follow from the Pythagorean theorem and the ratio.
Add resolution to get pixels per inch, a measure of sharpness.
The formula
Width = D × a ÷ √(a² + b²)Height = D × b ÷ √(a² + b²)
Worked example
Using the default values shown in the calculator:
| Diagonal (inches) | 27 |
|---|---|
| Aspect ratio width | 16 |
| Aspect ratio height | 9 |
| Horizontal pixels | 2560 |
| Vertical pixels | 1440 |
- Width = 27 × 16 ÷ √(16² + 9²) = 23.53 in; height = 13.24 in.
- That is 59.8 × 33.6 cm, with 108.8 pixels per inch.
Result:
| Width (in) | 23.53 |
|---|---|
| Height (in) | 13.24 |
| Width × height (cm) | 59.8 × 33.6 |
| Screen area (sq in) | 311.5 |
| Pixel density (PPI) | 108.8 |
Frequently asked questions
Is a 27-inch monitor 27 inches wide?
No. 27 inches is the diagonal. A 16:9 screen is about 23.5 inches wide and 13.2 inches tall.
What PPI looks sharp?
Around 110 PPI is typical at desk distance. Phones exceed 400 PPI because they are held closer.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.