Pixels Per Inch Calculator

PPI Formula:

\[ PPI = \frac{\sqrt{width_{pixels}^2 + height_{pixels}^2}}{diagonal_{inches}} \]

Pixels Per Inch (PPI):

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1. What is PPI?

PPI (Pixels Per Inch) is a measurement of the pixel density of electronic display devices like computer monitors, smartphones, and television screens. It indicates how many pixels are packed into one linear inch of display space.

2. How Does the Calculator Work?

The calculator uses the PPI formula:

\[ PPI = \frac{\sqrt{width_{pixels}^2 + height_{pixels}^2}}{diagonal_{inches}} \]

Where:

\( width_{pixels} \) — Horizontal resolution in pixels
\( height_{pixels} \) — Vertical resolution in pixels
\( diagonal_{inches} \) — Diagonal screen size in inches

Explanation: The formula calculates the diagonal resolution in pixels (using the Pythagorean theorem) and divides it by the physical diagonal size of the screen.

3. Importance of PPI Calculation

Details: PPI is crucial for understanding display quality. Higher PPI means sharper images and text, as more pixels are packed into each inch of screen space. This affects everything from graphic design work to everyday device usage.

4. Using the Calculator

Tips: Enter the screen's resolution (width and height in pixels) and its diagonal size in inches. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between PPI and DPI?
A: PPI refers to pixel density on screens, while DPI (dots per inch) refers to printer resolution. Though often used interchangeably, they are technically different.

Q2: What is a good PPI for a smartphone?
A: Most modern smartphones have PPIs between 300-500. A PPI of 300+ is generally considered "retina" quality at normal viewing distances.

Q3: Does higher PPI always mean better quality?
A: While higher PPI generally means sharper display, the human eye can't discern differences beyond certain thresholds at normal viewing distances.

Q4: How does PPI relate to screen size?
A: Two screens with the same resolution but different sizes will have different PPIs - the smaller screen will have higher PPI and appear sharper.

Q5: Can I calculate PPI without knowing the resolution?
A: No, you need both the resolution (in pixels) and the physical size (in inches) to calculate PPI accurately.