Screen DPI / PPI Calculator
Calculate display pixel density (PPI/DPI), dot pitch, aspect ratio, and Apple Retina viewing distances from screen resolution and diagonal size.
Display Specifications
Width in physical device pixels
Height in physical device pixels
Corner-to-corner viewable screen size
Classification: Standard Desktop (Sub-Retina)
Pixels disappear to human 20/20 vision at:
31.6" (80.3 cm)
Understanding Pixel Density in Modern High-Resolution Displays
Resolution alone tells only half the story. A 4K resolution on a 65-inch television offers significantly lower pixel density than 1440p on a compact 14-inch laptop. Understanding PPI and visual acuity thresholds allows digital artists, engineers, and hardware buyers to select optimal display sizes and configure operating system scaling factors without sacrificing workspace real estate.
Use Cases
- ✓UI/UX & Mobile App Asset Scaling
Determine appropriate image asset density multipliers (@1x, @2x, @3x) for iOS and Android responsive viewports based on device pixel density.
- ✓Monitor Buying & Workspace Ergonomics
Compare 27" 1440p vs 27" 4K monitors to decide whether integer OS scaling (200%) or fractional scaling will look crisp at your typical desk distance.
- ✓Gaming & GPU Performance Planning
Evaluate total megapixels rendered by graphics cards across 1080p, 1440p Ultrawide, and 4K UHD panels to benchmark frame rates.
- ✓Print & Graphic Design Proofing
Translate digital monitor PPI to commercial print 300 DPI standards to ensure typography and raster graphics reproduce crisply in physical media.
Key Capabilities
Retina Viewing Distance Formula
Computes the exact distance (based on human eye 1-arcminute visual acuity threshold) where individual screen pixels become imperceptible.
Dot Pitch (Pixel Pitch) Metric
Calculates the exact sub-millimeter distance from the center of one pixel cluster to the center of the next adjacent pixel.
Popular Hardware Presets
One-click loading of popular screens including Apple MacBook Pro 16", iPhone 15 Pro, 27" 4K monitors, and 55" OLED TVs.
Automatic Browser Screen Detection
Query your current connected device resolution and devicePixelRatio with a single click for instant calibration.
Frequently Asked Questions
What is the difference between PPI and DPI?
PPI (Pixels Per Inch) refers to digital display screen density—how many pixels are contained within one linear inch of screen surface. DPI (Dots Per Inch) originates from physical printing, referring to physical ink dots sprayed onto paper. In digital software contexts, the two terms are frequently used interchangeably.
What makes a display 'Retina'?
Apple defines a 'Retina' display not by a fixed PPI number, but by viewing distance. A screen is Retina when viewed at its intended distance (e.g. 10-12 inches for an iPhone, 20 inches for a laptop, 30 inches for a desktop) if the pixel density exceeds the resolving limit of a human eye with 20/20 vision (approximately 1 arcminute of angle).
How is PPI calculated?
First, calculate diagonal pixels using the Pythagorean theorem: d_p = sqrt(width^2 + height^2). Then, divide diagonal pixels by the physical diagonal screen size in inches: PPI = d_p / diagonal_inches.
Why does dot pitch matter?
Dot pitch (or pixel pitch) measures the physical size of individual pixels in millimeters. A smaller dot pitch (such as 0.15mm on a 4K 27" monitor vs 0.27mm on a 1080p 24" monitor) produces sharper text, smoother curved lines, and reduced pixelation.
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