This PPI calculator works out the pixel density of any monitor, laptop or phone screen from its resolution and diagonal size, so it doubles as a pixel density calculator for any display. Choose a monitor, laptop, phone, tablet or TV from the list, or type any resolution and size in inches or centimeters, and it shows pixels per inch, pixels per centimeter, dot pitch, total pixels and the screen's width and height. It also tells you the distance at which single pixels disappear for normal eyesight and how sharp the screen looks from your own seat, and suggests a Windows scaling level for high PPI monitors. Use my screen fills in the resolution your browser reports.
How to use the PPI calculator
- Pick a screen under Common screens, or type the resolution as width × height in pixels.
- Enter the diagonal size. Switch to Centimeters if your screen is sold in centimeters.
- Set your viewing distance, or press Phone, Laptop, Desk or TV for a typical one.
- Read the results. The verdict line says whether single pixels are visible from that distance.
- To check the screen in front of you, press Use my screen, then type its diagonal.
- Press Copy results for a plain text summary you can paste into a note or a comparison.
What the results mean
| Result | What it tells you | Example: 27 in, 2560 × 1440 |
|---|---|---|
| Pixel density | Pixels per inch along any line on the screen | 108.8 PPI, 42.8 per cm |
| Dot pitch | Width of one pixel in millimeters | 0.233 mm |
| Total pixels | Width × height in pixels, in megapixels | 3.69 MP |
| Sharp beyond | Distance where one pixel shrinks below what 20/20 eyes can see | 31.6 in, 80 cm |
| At your distance | Pixels per degree of your view. 60 or more looks fully smooth | 49 at 26 in |
| Suggested scaling | The Windows scale that makes text a comfortable size | 100% |
How PPI is calculated
PPI is the number of pixels along the diagonal divided by the diagonal's length in inches. For a 27 inch screen at 2560 × 1440:
- Pixels along the diagonal: √(2560² + 1440²) = 2937.2
- Pixel density: 2937.2 ÷ 27 = 108.8 PPI
- Dot pitch: 25.4 mm ÷ 108.8 = 0.233 mm
- Width: 27 × 2560 ÷ 2937.2 = 23.5 in, and height: 27 × 1440 ÷ 2937.2 = 13.2 in
Makers round the diagonal, so their own figure can differ from yours by one or two PPI.
What is a good PPI?
It depends on how far away you sit. These are typical ranges:
| Screen | Usual distance | Common PPI | Looks sharp from |
|---|---|---|---|
| 24 in 1920 × 1080 monitor | 60 to 70 cm | 92 | 95 cm |
| 27 in 2560 × 1440 monitor | 60 to 70 cm | 109 | 80 cm |
| 27 in 3840 × 2160 monitor | 60 to 70 cm | 163 | 53 cm |
| 34 in 3440 × 1440 ultrawide | 70 to 80 cm | 110 | 80 cm |
| 14 to 16 in laptop | 45 to 55 cm | 140 to 250 | 35 to 62 cm |
| 6 to 7 in phone | 25 to 35 cm | 400 to 460 | 19 to 22 cm |
| 65 in 4K TV | 2 to 3 m | 68 | 1.3 m |
A 24 inch 1080p monitor is the one where many people notice soft text. At the same distance a 27 inch 1440p screen looks a little sharper, and a 27 inch 4K looks crisp.
When pixels stop being visible
Eyes with 20/20 vision can separate details about one arcminute apart, a sixtieth of a degree. Once a single pixel covers less than that, you can no longer pick it out, and the screen looks continuous. The distance where that happens is about 3438 ÷ PPI in inches, which is the Sharp beyond readout.
The At your distance readout shows pixels per degree from your seat. Below about 45 you see jagged edges on fine text and lines. Between 45 and 60, pixels show only on close inspection. At 60 or more the screen looks smooth to normal eyes, and people with sharper vision than 20/20 can still benefit from a little more.
Scaling on high PPI screens
At 100% Windows draws text for about 96 PPI, so on a dense screen everything looks tiny. Scaling enlarges it while keeping the extra sharpness:
- Windows: open Settings > System > Display and choose a value under Scale. The calculator suggests the step that brings text close to the size it has on a 105 PPI screen, and tells you how much desktop space that leaves.
- Mac: open System Settings > Displays and pick a size between Larger Text and More Space. macOS looks sharpest at exactly twice the pixels, around 220 PPI, which is why a 27 inch 5K screen is an Apple favorite. A 27 inch 4K set to look like 2560 × 1440 is drawn larger and scaled down, which is slightly softer.
Measuring your own screen
Use my screen reads the resolution and scaling your browser reports, and multiplies them to get the real pixel count. A browser cannot measure physical size, so you still need the diagonal: find it on the box or the maker's page, or measure the visible picture from one corner to the opposite corner, not including the frame. To see more about your display, the screen resolution test lists everything your browser knows about it.
PPI for printing
Prints use the same idea in reverse. For sharp photo prints you need about 300 pixels for every inch of paper, so an 8 × 10 inch print needs 2400 × 3000 pixels and a 4 × 6 inch print needs 1200 × 1800. Posters viewed from a distance look fine at 150 PPI or less.
Related screen tools
The aspect ratio calculator works out ratios and resizes images and video without stretching them. The monitor size calculator draws two screens side by side to scale, which helps when you compare a 27 inch monitor with an ultrawide. If you bought a 4K screen, the 4k monitor test confirms it is really running at 3840 × 2160.
What a PPI calculator cannot tell you
PPI is calculated from the stated diagonal and assumes square pixels in a regular grid. Many phone OLED screens share subpixels between pixels, so they look slightly less sharp than their PPI suggests. Rounded corners, notches and the curve of a curved monitor do not change the result. PPI also says nothing about color, brightness or motion.
PPI calculator questions
What is a good PPI for a monitor?
At a normal desk distance of 60 to 70 cm, about 90 to 110 PPI looks fine at 100% scaling, which is a 24 inch 1080p or a 27 inch 1440p screen. From about 140 PPI, such as a 27 inch 4K, text looks crisp, but you will use 150% scaling so it is not too small.
How do I find my screen's PPI?
Press Use my screen to fill in your resolution, then type the diagonal from the maker's specifications or measure the visible picture from corner to corner. The calculator divides the number of pixels along the diagonal by its length.
What is the difference between PPI and DPI?
PPI counts the pixels per inch on a screen or in a digital image. DPI counts the ink dots per inch a printer lays down, and printers use several dots for each pixel. Mouse makers also use DPI for sensor sensitivity, which is unrelated. For screens, PPI is the correct term.
How far should I sit from a 4K monitor?
On a 27 inch 4K screen, single pixels disappear for 20/20 eyes from about 53 cm, or 21 inches, so a normal desk distance is already beyond that. On a 32 inch 4K the distance is about 63 cm, or 25 inches.
What PPI counts as Retina?
Apple uses the name for screens dense enough that pixels vanish at their normal viewing distance: about 220 PPI and up on Macs, and 326 PPI and up on iPhones. The Sharp beyond readout here uses the same idea for any screen and any distance.
Is a higher PPI always better?
Not past the point your eyes can see. A 65 inch 4K TV has only 68 PPI, yet looks sharp from the sofa because you sit 2 to 3 meters away. Very high PPI on a desktop monitor also needs scaling and a faster graphics card for games.