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Hardware Engineering
DPI / PPI Calculator
Screen resolution (like 1920x1080) only tells half the story. The true measure of a display's "sharpness" is its Pixels Per Inch (PPI). A large TV and a small phone can have the same resolution, but the phone will look much sharper because its pixels are packed closer together.
How to Calculate PPI
- 1. Enter the Width and Height of your screen in pixels.
- 2. Enter the Diagonal Size of the screen in inches (e.g., 6.1 for an iPhone).
- 3. The tool calculates the Pixel Density using the Pythagorean theorem.
- 4. Use the Invert feature to determine what resolution you'd need for a specific target PPI.
The PPI Formula
PPI = √(w² + h²) / d
Where w = Width, h = Height, and d = Diagonal size
DPI vs. PPI
DPI (Dots Per Inch) refers to physical drops of ink on paper. PPI (Pixels Per Inch) refers to light-emitting pixels on a digital screen. While often used interchangeably, they serve different industries.
Visual Acuity
The "Retina" standard implies that at a normal viewing distance, the human eye cannot distinguish individual pixels. This usually occurs around 300 PPI for phones.
Display FAQs
What is a 'good' PPI for a laptop?+
Does a higher PPI drain battery?+
Can I use this for printing?+