📺 DPI / PPI Calculator
Calculate pixel density for any screen — monitors, phones, tablets, TVs.
Calculate dots per inch or pixels per inch for any screen or image. Enter resolution width, height, and diagonal size — or select from common presets including 1080p, 1440p, 4K, and Retina displays. Results show pixel density, dot pitch, aspect ratio, and megapixel count. Useful for designers assessing image sharpness and screen clarity.
📋 When to Use the DPI & PPI Calculator
Choosing a monitor? The DPI & PPI Calculator helps designers, photographers, and developers compare screen sharpness before buying. Use it to check if your laptop display qualifies as Retina-quality, verify a spec sheet's PPI claims, or compare the pixel density of different monitors, phones, and tablets. The presets cover common configurations — 1080p at 24", 4K at 27", MacBook Retina, and flagship smartphones — so you can benchmark any screen instantly. All math runs client-side; no data leaves your browser.
⚙️ How the DPI & PPI Calculator Works
PPI (Pixels Per Inch) is computed using the Pythagorean theorem: diagonal pixels = √(width² + height²), then divided by the physical diagonal size in inches. Dot pitch follows from the inverse: (diagonal inches ÷ diagonal pixels) × 25.4 to convert to millimeters. The result is categorized by density thresholds — 0–99 PPI (Standard), 100–159 (HD Display), 160–219 (Full HD), 220–299 (Quad HD), 300–399 (Retina Quality), and 400+ (Super Retina). Since PPI and DPI are interchangeable on digital displays, both show the same value. All computation runs instantly in your browser using your device's processor.
How to Use the DPI / PPI Calculator
- Choose a preset — click one of the common display presets (1080p 24", 4K 27", MacBook Retina, etc.) to quickly see pixel density for popular screens.
- Or enter custom values — type your screen's width in pixels, height in pixels, and diagonal size in inches.
- Read your results instantly — PPI (pixels per inch), DPI (dots per inch), and Dot Pitch (mm) update in real time as you type.
- Check the quality category — the tool classifies your display from "Standard" to "Super Retina" so you know how sharp it is compared to industry benchmarks.
Frequently Asked Questions
What's the difference between DPI and PPI?
PPI (Pixels Per Inch) describes the pixel density of a digital display. DPI (Dots Per Inch) is technically a print term for ink dots. On screens, they're often used interchangeably — our calculator shows the same value for both since one screen pixel = one dot in display context.
What is a good PPI for a monitor?
For desktop monitors viewed at arm's length, 90–110 PPI is standard and comfortable. 110–160 PPI is sharp (common on 1440p 27" and 4K 32" displays). Above 220 PPI is "Retina" quality where individual pixels become invisible at normal viewing distance.
What is Dot Pitch and why does it matter?
Dot pitch is the physical distance between pixel centers, measured in millimeters. Smaller dot pitch means sharper image. A 24" 1080p display has ~0.277mm dot pitch, while a 27" 4K display has ~0.155mm — nearly twice as sharp.
How is PPI calculated?
PPI = √(width² + height²) / diagonal inches. This formula uses the Pythagorean theorem to find the diagonal resolution in pixels, then divides by the physical diagonal size.