PPI calculator computes pixel density for any screen — phone, laptop, monitor, or TV.
About this calculator
PPI calculator computes pixel density for any screen — phone, laptop, monitor, or TV. Enter horizontal resolution, vertical resolution, and diagonal size in inches. You get PPI, dot pitch in millimetres, and total megapixels.
A 24-inch 1920×1080 monitor is about 92 PPI — fine for desk use. A 6.7-inch phone at 1080×2400 hits ~390 PPI — sharp at arm's length. Apple Retina marketing roughly targets 300+ PPI at phone distance.
Compare aspect ratio with [[aspect-ratio]]. For print design (300 DPI vs screen PPI) see [[percentage]] scaling. Engineers sizing HMI panels can cross-check readable font sizes against PPI.
Common uses
- Comparing 27-inch 1440p vs 4K monitor sharpness before purchase
- Verifying phone spec sheet PPI claim (e.g. iPhone vs Samsung)
- Calculating dot pitch for industrial HMI display selection
- Student homework on display technology metrics
- Checking if old 1366×768 laptop is too low-PPI for coding
Frequently asked questions
What PPI is a 24-inch 1920×1080 monitor?
About 92 PPI. Diagonal pixels = √(1920² + 1080²) ≈ 2203. Dividing by 24 inches gives 91.8 PPI. Adequate for desktop use at 60–70 cm viewing distance.
Is 300 PPI necessary for a phone screen?
At 25–30 cm viewing distance, most people cannot resolve individual pixels above ~300 PPI. Flagship phones at 400+ PPI exceed human acuity but improve sub-pixel rendering of text.
What is the difference between PPI and DPI?
PPI counts screen pixels per inch. DPI (dots per inch) refers to printer ink dots. They measure different things — a 300 DPI print can look sharper than a 100 PPI screen at close range.
How do I calculate PPI for a 15.6-inch 1920×1080 laptop?
Enter 1920, 1080, and 15.6. Result is about 141 PPI — noticeably sharper than a 24-inch panel at the same resolution because the same pixels pack into a smaller area.