What is PPI/DPI Calculator?

Calculate the pixel density (PPI) of screens and displays by entering the resolution and physical dimensions. Useful for comparing display sharpness, determining if a monitor is Retina-quality, and calculating print DPI for images.

Switch between screen and print modes. Screen mode takes resolution (width × height) and diagonal inches, returns pixels per inch plus a class label from Low through Ultra High. Print mode flips it: enter the image pixel dimensions and target print size to see the effective DPI and a print-quality rating. Built-in presets cover common monitors, MacBooks, iPhone 15 Pro, and iPad Pro.

How to use

1. Enter your display's resolution in pixels (width and height) and its diagonal size in inches.
2. The calculator instantly shows the PPI value along with display classification (standard, Retina, etc.).
3. Use the print DPI mode to check if an image has enough resolution for a given print size.

When to use

• Comparing two monitors with different sizes and resolutions before buying.
• Checking whether a photo will print sharp at 8x10 or wall-poster size.
• Confirming a UI mockup is built at the correct logical density for Retina hardware.

Result

A 27-inch 4K monitor (3840x2160) at 27 inches diagonal has a PPI of 163, which is above the Retina threshold at normal viewing distance.

FAQ

What PPI counts as Retina-quality?

Apple originally drew the line at 300 PPI for phones held about 10 inches away, and 220 PPI for laptops at arm's length. Above those values individual pixels become hard to resolve. Modern phones routinely reach 450 PPI, well past the perception ceiling.

Does higher PPI always mean a better display?

Only up to a point. Past 300 PPI on a phone or 200 PPI on a desk monitor, the extra density costs battery and GPU power for no visible gain. Refresh rate, colour gamut, and contrast often improve perceived quality more.

Is DPI the same as PPI?

Strictly no. PPI describes pixels on a screen, DPI describes printer ink dots per inch. Casually they're swapped because both measure spatial density. This tool uses DPI when talking about print and PPI when talking about displays.

What DPI do I need for printing?

300 DPI is the standard for photo prints viewed in hand. Magazines drop to 250-300 DPI. Large prints viewed from a few metres can look fine at 150 DPI, and billboards print at 30 DPI because nobody stands close enough to see the dots.

How does viewing distance change the math?

The minimum PPI for sharp vision halves as the distance doubles. A TV watched from 3 metres only needs about 80 PPI. A phone held 30 cm away needs around 350 PPI. Screen mode shows the distance at which your display's pixels stop being resolvable, so you can sanity-check the result against how far away you actually sit.

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