Pixel Density (PPI) Calculator
Calculate pixels per inch (PPI) from your screen's resolution and diagonal size.
About Pixel Density (PPI) Calculator
Pixels per inch (PPI) describes how tightly a display packs its pixels, and it is the honest measure of sharpness because resolution alone misleads: a 4K TV at 65 inches looks similar to a 1080p monitor at 32 inches. A PPI calculator gives you that number for any screen.
The tool finds the diagonal resolution with the Pythagorean theorem, √(width² + height²), and divides it by the physical diagonal in inches. A 1920×1080 display at 24 inches comes out to roughly 92 PPI. It also reports total pixel count. PPI is fixed by hardware, so it is a number you read rather than adjust, but it is essential for comparing displays and reasoning about image sizing.
Monitor buyers use it to compare sharpness across sizes and resolutions, designers and photographers need it to size images correctly for print or web, and developers building for specific devices use it to understand pixel ratios. Phone and laptop shoppers also check it when a small screen claims high resolution.
How to Use
- Enter the screen's width and height in pixels.
- Enter the diagonal size in inches.
- Read the PPI and total pixel count.
Example
1920×1080, 24-inch diagonal ≈ 92 PPI
The diagonal pixel count (√(1920² + 1080²)) is divided by the physical diagonal in inches to get PPI.
FAQ
What is a good PPI for a monitor?
Most desktop monitors are 90-110 PPI. Phones and laptops range 200-500 PPI, where individual pixels become invisible.
Why does PPI matter?
Higher PPI means crisper text and images. It's also the number you need to reason about image sizing at scale.
Does resolution alone determine sharpness?
No — a 4K screen at 65 inches looks similar to a 1080p screen at 32 inches. PPI is the honest measure of sharpness.
What PPI do I need for crisp text?
For desktop monitors, 90-110 PPI is typical and text looks fine. Around 200+ PPI, individual pixels become essentially invisible at normal viewing distance, which is why phones and modern laptops feel so sharp.
How is PPI related to the device pixel ratio?
CSS pixels and physical pixels differ on many devices. A 2x device pixel ratio means four physical pixels make one logical pixel, so PPI overstates the logical density and sharpness comes from both the PPI and the ratio.