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PPI Calculator

Free Calculator

Turn your screen resolution and diagonal size into pixels per inch — the pixel density that decides how crisp your assets look.

100% private

Runs in your browser — no numbers leave your device.

Your screen

Screen width in pixels — the horizontal resolution.

Screen height in pixels — the vertical resolution.

Diagonal screen size in inches, corner to corner.

Pixels per inch (PPI)

505

Pixel density of the screen — higher PPI means sharper text and images.

Diagonal resolution (px)

3,079

The diagonal pixel count, √(width² + height²).

How it works

1

Enter resolution

Add the screen width and height in pixels.

2

Add diagonal size

Enter the diagonal screen size in inches.

3

We do the maths

We find the diagonal pixel count, then divide by inches.

4

Read your PPI

Pixel density and diagonal resolution update live.

Design assets that stay razor-sharp

Reverze rebuilds your App Store screenshots at pixel-perfect density for every device.

What is a PPI calculator and how do you calculate PPI?

PPI, or pixels per inch, measures the pixel density of a display — how many pixels are packed into each linear inch of the screen. A PPI calculator turns three numbers into that density: the screen's width in pixels, its height in pixels, and its diagonal size in inches. It first finds the diagonal resolution with the Pythagorean theorem — √(width² + height²) — then divides that pixel count by the diagonal size in inches to give you the PPI.

Pixel density matters because it decides how crisp your text, icons and screenshots look. A higher PPI packs more detail into the same physical space, so assets exported at too low a resolution appear soft or pixelated on dense modern displays. Knowing the target device's PPI helps you design and export App Store creative at the right resolution — exactly what Reverze automates so every screenshot stays razor-sharp across iPhone, iPad and Android.

Frequently asked questions

How do I calculate PPI?
Find the diagonal resolution in pixels with √(width² + height²), then divide by the diagonal screen size in inches. For example, a 1290 × 2796 screen has a diagonal of about 3079 px; on a 6.1-inch display that is roughly 505 PPI. This calculator does it instantly.
What is the difference between PPI and DPI?
PPI (pixels per inch) describes the density of a digital display, while DPI (dots per inch) describes the density of ink dots a printer lays down. They are often used interchangeably, but PPI is the correct term for screens and DPI for print.
What is a good PPI for a phone screen?
Modern smartphones typically sit between 400 and 500+ PPI, which is well past the roughly 300 PPI at which the human eye stops noticing individual pixels at normal viewing distance. Tablets and laptops are usually lower because they are held or viewed farther away.
Does higher PPI mean better image quality?
Higher PPI means finer detail, but only if your assets are exported at a matching resolution. A low-resolution image will still look soft on a high-PPI screen. That is why exporting screenshots at the device's native pixel density is key — and what Reverze handles automatically.