Screen PPI Calculator
Calculate pixels per inch, dot pitch, and aspect ratio from a screen's resolution and diagonal size.
Processed locally in your browser — nothing is uploaded.
Screen PPI Calculator
Results
- Pixel density
- 91.79 PPI
- Dot pitch
- 0.2767 mm
- Total pixels
- 2,073,600
- Aspect ratio
- 16:9
About Screen PPI Calculator
Enter a resolution and diagonal size to get pixel density (PPI = √(w² + h²) ÷ diagonal), dot pitch in millimeters, total pixel count, and the aspect ratio. Presets cover common monitors and a modern phone panel.
It also reads your current screen via the browser for a quick sanity check — note that browsers report CSS pixels times devicePixelRatio, which may not match the panel's true native resolution.
Common uses
- Compare sharpness between a 24" 1080p and a 27" 1440p monitor before buying
- Check whether text will be readable at 100% scaling on a prospective display
- Find the dot pitch a spec sheet leaves out
Example
Input
1920 × 1080 at 24"
Output
91.79 PPI · 0.2767 mm dot pitch · 16:9
Frequently asked questions
How is PPI calculated?
PPI is the diagonal resolution in pixels divided by the diagonal size in inches: √(width² + height²) ÷ diagonal. A 27-inch 2560 × 1440 monitor works out to about 109 PPI.
Does this calculator send my screen details to a server?
No. All the math and the optional current-screen detection run in your browser with JavaScript — no resolution, size, or device information is transmitted or stored anywhere.
What is dot pitch and how does it relate to PPI?
Dot pitch is the distance between adjacent pixel centers, computed as 25.4 ÷ PPI millimeters. It is the inverse of pixel density: a lower dot pitch means pixels sit closer together and the image looks sharper.
Why doesn't the detected resolution match my monitor's specs?
Browsers report screen size in CSS pixels multiplied by devicePixelRatio, which reflects your operating system's scaling rather than the panel's native pixel grid. Enter the resolution from the spec sheet for an exact PPI figure.
Is PPI the same as DPI?
In casual use the terms are interchangeable, but strictly PPI describes pixels on a display while DPI describes ink dots laid down by a printer. For screens, PPI is the technically correct measure this tool computes.