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Hndy Tools

PPI Calculator (Pixels Per Inch)

Calculate pixel density, dot pitch, total megapixels, and aspect ratio for any screen or print

Calculator
Display
Pixels
Resolution

About This Tool

This PPI Calculator finds pixels per inch (PPI) and pixels per centimeter (PPcm) for any display. Enter the screen resolution in pixels and the diagonal size in inches or centimeters, and the tool instantly computes pixel density (PPI, PPI², PPcm), dot pitch in millimeters, the diagonal length in pixels, total pixel count (megapixels), and the aspect ratio in both common and decimal form.

PPI follows the Pythagorean theorem: diagonal in pixels = √(width² + height²), then PPI = diagonal in pixels ÷ diagonal in inches. Dot pitch = (diagonal inches ÷ diagonal pixels) × 25.4 mm. Higher PPI means a sharper screen — phones typically hit 300—460 PPI, laptops 150—250, and desktop monitors 90—165.

Designing for a specific display? Pair this with the Color Contrast Checker to ensure text legibility at your target density, or use the Color Picker to grab accurate hex values for UI work. For photography workflows, the Camera Storage Calculator helps plan how many photos fit a memory card at a given megapixel count.

Browse more tools on the Display tag page. All calculations are performed locally in your browser — no data is sent to any server.

Frequently Asked Questions (FAQ)

What is PPI (Pixels Per Inch)?
PPI measures pixel density — the number of pixels in a one-inch line on a display. Higher PPI means sharper text and images. PPI is calculated as the diagonal length in pixels divided by the diagonal length in inches: PPI = √(width² + height²) ÷ diagonal inches.
How is PPI different from DPI?
PPI refers to display pixel density, while DPI (dots per inch) refers to print resolution. They are often used interchangeably, but for screens use PPI and for printers use DPI. A 300 PPI/DPI print is considered photographic quality.
What is dot pitch and why does it matter?
Dot pitch is the physical distance between the centers of two adjacent pixels, measured in millimeters. Smaller dot pitch means a sharper display. It is calculated as (diagonal in inches ÷ diagonal in pixels) × 25.4 mm.
What PPI do I need for a sharp display?
For phones, 300+ PPI is typical and minimally "retina". For laptops, 200+ PPI feels crisp. Desktop monitors around 110—163 PPI are common at standard viewing distance. 4K TVs at 55"+ can have under 80 PPI but look sharp from across the room due to viewing distance.
Can I use this calculator for print resolution?
Yes. Enter the print width and height in pixels (width = DPI × inches), and the diagonal as the physical size of the print. The PPI output tells you the print resolution — aim for 300 PPI for photo-quality prints.
Is my data processed securely?
All processing happens entirely in your browser. No data is sent to any server — your screen specifications never leave your device.

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