PPI / Pixel Density Calculator
Find a screen’s pixels-per-inch, dot pitch, and sharpness from its resolution and diagonal size.
px
px
in
Sharpness: Standard
- 1
Diagonal pixels
√(1,920² + 1,080²) = 2,203Pythagorean theorem across the pixel grid. - 2
Pixel density (PPI)
2,203 ÷ 15.6 = 141.2
How does this calculator work?
Pixel density (PPI) equals the diagonal pixel count, √(width² + height²), divided by the screen’s diagonal in inches. Dot pitch is 25.4 ÷ PPI in millimetres. Around 300 PPI or more looks retina-sharp at normal viewing distance, while lower values reveal individual pixels up close.
Formula
How this is calculated
Enter the horizontal and vertical pixel counts (the resolution) and the physical diagonal of the screen in inches. The diagonal pixel count is the Pythagorean combination of the two axes: diagonalPixels = √(width² + height²). Dividing that by the diagonal in inches gives pixels per inch (PPI), the core measure of how densely packed the pixels are.
Dot pitch is the physical spacing between adjacent pixels and is the inverse of density: dotPitch = 25.4 ÷ PPI, where 25.4 is the number of millimetres in one inch. A higher PPI therefore means a smaller dot pitch and a finer image. Total resolution is simply width × height, shown here in megapixels.
As a rule of thumb, displays around 300 PPI or higher appear “retina-sharp” at a typical viewing distance, meaning individual pixels are no longer resolvable by the average eye. This threshold scales with distance: phones held close need higher PPI than TVs viewed across a room, so treat the bands as a guide for hand-held and desktop viewing rather than an absolute limit. All inputs must be positive numbers.
Frequently asked questions
At normal hand-held or desktop viewing distance, roughly 300 PPI and above is considered retina-sharp because pixels become indistinguishable to the typical eye. Devices viewed from farther away can look just as sharp at lower PPI.
For screens the terms are used interchangeably, but strictly PPI (pixels per inch) describes displays while DPI (dots per inch) describes printers. This calculator reports display PPI.
Dot pitch is the centre-to-centre distance between neighbouring pixels, in millimetres. It equals 25.4 divided by the PPI, so a denser screen has a smaller dot pitch.
Also known as
TG we-Calculate Editorial Team. (2026). PPI / Pixel Density Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ppi-pixel-density-calculator
TG we-Calculate Editorial Team. "PPI / Pixel Density Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/ppi-pixel-density-calculator.
TG we-Calculate Editorial Team, "PPI / Pixel Density Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ppi-pixel-density-calculator
@misc{wecalculate_ppi_pixel_density_calculator, title = {PPI / Pixel Density Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ppi-pixel-density-calculator}}, year = {2026}, note = {TG we-Calculate} }
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