PPI Calculator

PPI stands for pixels per inch and measures how tightly packed a screen's pixels are, in other words its pixel density. A higher PPI means smaller, less visible pixels and sharper text and images. It is the single number that ties a display's resolution to its physical size, which is exactly what this PPI calculator works out for you.

Find the diagonal in pixels with the Pythagorean theorem — the square root of width squared plus height squared — then divide that by the diagonal in inches. For example, a 2560x1440 screen at 27 inches works out to about 109 PPI. Rather than doing the maths by hand, enter your resolution and diagonal in the pixels per inch calculator above and it shows the result instantly.

PPI (pixels per inch) describes pixels on a screen, while DPI (dots per inch) describes the ink dots a printer lays on paper. The terms get used interchangeably, but they answer different questions: PPI tells you how sharp a display looks, and DPI tells you how fine a print will be. If you searched for a DPI to PPI calculator, note that the on-screen answer is the PPI figure this tool gives you.

Resolution is the total pixel count, such as 1920x1080, while PPI is how densely those pixels are packed into the physical screen. The same resolution can look razor-sharp on a small phone yet show visible pixels on a large TV, because the pixels are spread over very different areas. PPI is the figure that combines resolution and screen size into one measure of sharpness.

For desktop monitors viewed at arm's length, roughly 90 to 140 PPI is the sweet spot: sharp text without needing heavy scaling. Below about 80 PPI pixels start to look chunky, while very high densities usually need operating-system scaling so things are not too small. Pop a couple of monitors into the calculator above to compare them before you buy.

Phones are held much closer to your eyes than a monitor, so they target far higher densities — typically 300 PPI or more. Around 300+ PPI is where most people stop noticing individual pixels at normal phone-reading distance, which is the basis for Apple's Retina marketing. Many modern handsets push 400 to 500 PPI for extra-smooth text and edges.

Printing is measured in DPI rather than PPI, and the common standard for sharp photo prints is around 300 DPI at the final print size. Screens generally sit well below that, often near 100 PPI, which is fine for viewing but not directly comparable to print. This calculator reports the screen-side pixel density; for print you would size your image to the desired inches at roughly 300 DPI instead.

Not always. Higher PPI makes everything sharper, but it also makes text and icons smaller, so a very dense panel usually needs scaling to stay readable, and it asks more of your GPU since more pixels are drawn each frame. Beyond the point where your eye can no longer see individual pixels, extra density adds little visible benefit. The right PPI depends on screen size and how far away you sit.

There is no single magic number because it depends on viewing distance. As a rough guide, about 110+ PPI is comfortable for desktop monitors, roughly 150+ looks crisp, and phones held closer typically need 300+ PPI for pixels to become indistinguishable. Run your own numbers through the calculator to see where your screen lands on that scale.

You need two things: your display's native resolution and its diagonal size in inches. The resolution is in your operating-system display settings, and the diagonal is the figure a screen is marketed with, such as 24, 27 or 32 inches. Type both into the pixels per inch calculator above and it returns your exact PPI, along with dot pitch, megapixels and aspect ratio.