ConverterHub

PPI (Pixel Density) Calculator

What is my screen’s PPI?

Result

108.79
0.23 mm
3.69 MP

How it is calculated

Pixel density is the number of pixels per inch along the diagonal: PPI = √(w² + h²) ÷ diagonal, where w and h are the resolution in pixels and the diagonal is the screen size in inches. The tool also derives the dot pitch, the distance between pixel centres: pitch = 25.4 ÷ PPI in mm, and the total megapixels, w × h ÷ 1,000,000. All inputs must be above zero and the results have two decimals. Higher PPI means a sharper image at the same size. PPI depends only on resolution and physical size; viewing distance decides whether the difference is visible.

Worked example

A 27-inch monitor with 2560 × 1440 pixels. Diagonal in pixels: √(2560² + 1440²) = √8.63 million ≈ 2,937.3. PPI = 2,937.3 / 27 = 108.79. Dot pitch = 25.4 / 108.79 = 0.23 mm. Megapixels = 2560 × 1440 / 1,000,000 = 3.69 MP. The same resolution on a 32-inch panel would be only about 91.8 PPI.

Try this example →

Common mistakes

  • Entering the screen size in centimetres; the diagonal must be in inches.
  • Confusing PPI with DPI, which is a printing term for dots per inch.
  • Using the screen width or height instead of the diagonal.
  • Entering the physical resolution of a scaled display; the tool needs the native pixel count.

About this calculator

This calculator determines a screen's pixel density (PPI, pixels per inch) from its horizontal and vertical resolution and its diagonal size, along with related figures like dot pitch (the physical distance between pixels) and total megapixels. Higher PPI means individual pixels are packed more tightly together, which is what makes text and images look sharp rather than grainy at normal viewing distance.

This figure matters to anyone comparing monitors, phones or TVs on paper specs before buying, since a larger screen with the same resolution as a smaller one actually has a lower PPI and will look noticeably less crisp. Designers and developers also use PPI to decide how large to make interface elements and images so they render sharply across devices with different pixel densities, and photographers reference it when deciding print sizes that will still look sharp to the naked eye.

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