Why use this calculator
PPI (pixels per inch) determines how sharp and detailed a screen appears. Higher PPI means finer detail, which matters for reading text, viewing photos, and design work.
How to use it
Enter the screen resolution in pixels (width and height) and the physical diagonal size in inches. The calculator determines the pixel density and rates the display sharpness.
The formula
PPI = sqrt(Width^2 + Height^2) / Diagonal (inches); Dot Pitch = 25.4 / PPI
Worked examples
27-inch 2560x1440 monitor
~109 PPI, 3.69 megapixels, Standard rating
6.1-inch 2532x1170 smartphone
~460 PPI, 2.96 megapixels, Retina / Excellent rating
When people use it
- Comparing monitor and TV sharpness before purchasing
- Evaluating smartphone display quality
- Determining optimal viewing distance for screens
- Choosing displays for graphic design or photo editing
Tips
- A PPI above 300 is generally considered 'Retina' quality where individual pixels are not visible.
- Larger screens need higher resolutions to maintain the same PPI.
- For desktop monitors viewed at arm's length, 100+ PPI is generally acceptable.
- Dot pitch is the physical distance between pixel centers in millimeters.
Questions people ask
- What PPI is considered good?
- For smartphones, 300+ PPI is excellent. For desktop monitors, 100-150 PPI is standard, and 200+ PPI is considered very sharp.
- Does higher PPI always mean better?
- Higher PPI means sharper images, but the benefit depends on viewing distance. A TV viewed from 10 feet away does not need as high a PPI as a phone held 12 inches from your face.
- What is dot pitch?
- Dot pitch is the distance in millimeters between the centers of adjacent pixels. Smaller dot pitch means higher pixel density and sharper display.