Pixel Size Calculator
Enter a screen's diagonal size in inches and its resolution in pixels. The calculator gives the pixel density, the size of each pixel, the screen's width and height and the distance at which you stop seeing the pixels.
- PPI and pixel pitch
- Screen width and height
- Viewing distance
Use the advertised diagonal. The visible area can be slightly smaller.
Pixel density is how many pixels fit into an inch of screen. A phone packs over 400 pixels per inch, a desktop monitor around 100 to 160, and a big TV less than 80. What matters is how far away you sit: the further back, the less density you need for a sharp picture.
Pixel density chart
Common screens. Search for a screen.
| Screen | Resolution | PPI | Pixel pitch (mm) | Pixels blend at (m) |
|---|---|---|---|---|
| 6.1 in phone | 1179 × 2556 | 461 | 0.055 | 0.19 |
| 13.3 in laptop | 2560 × 1600 | 227 | 0.112 | 0.38 |
| 24 in monitor | 1920 × 1080 | 92 | 0.277 | 0.95 |
| 27 in monitor | 2560 × 1440 | 109 | 0.233 | 0.8 |
| 27 in 4K | 3840 × 2160 | 163 | 0.156 | 0.54 |
| 32 in 4K | 3840 × 2160 | 138 | 0.184 | 0.63 |
| 55 in 4K TV | 3840 × 2160 | 80 | 0.317 | 1.09 |
| 65 in 4K TV | 3840 × 2160 | 68 | 0.375 | 1.29 |
Blend distance is where one pixel covers one arcminute of your view, the limit for normal eyesight.
Screen size and density
Three resolutions. Slide the diagonal.
The inset shows pixels magnified. Bigger squares mean bigger pixels and a coarser image up close.
How to work out PPI
Pythagoras. Step through it.
Diagonal pixels
√(width² + height²).
Pixel pitch is the distance from the centre of one pixel to the next. LED video walls are sold by pitch, such as P2.5.
Phone, monitor or TV
Density by use. Compare them.
Held close, needs very high density.
At arm's length.
Across the room.
Apple's Retina label means the pixels blend at typical viewing distance, not a fixed PPI.
Choosing a screen
Sharpness checks. Tick each item.
Tick each item as you go.
Scaling matters. A 27 in 4K monitor is often run at 150% scaling, so text is sharp but the same size as on a 1440p screen.
What you get
Pixel facts. Each tile explains one result.
Pixel density.
In mm.
cm and inches.
Total pixels.
Where pixels vanish.
Screen width and height come from the diagonal and the aspect ratio of the resolution.
Frequently Asked Questions
No question matches that search.
What is PPI?
Pixels per inch, the number of pixels along one inch of screen.
How do I calculate PPI?
√(width² + height²) ÷ diagonal in inches.
What PPI is a 27 inch 4K monitor?
About 163 PPI.
What PPI is good for a monitor?
About 110 or more at arm's length looks sharp.
What is pixel pitch?
The distance between pixel centres, 25.4 ÷ PPI in mm.
At what distance is 4K worth it on a 55 in TV?
Closer than about 1.1 m you can see 4K detail fully; further back, it still looks smoother.
Is higher PPI always better?
Only up to the point your eyes can see at your viewing distance.
Know your pixels
Enter the diagonal and resolution to get density, pitch and size. Compare it with how far you sit, and you will know whether a screen will look sharp to you.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.