Pixels to Inches
Type a pixel count and the DPI it will be used at. Nothing is uploaded — there is no file here at all.
Physical size
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The other way round
A physical size, at the same DPI, back into pixels.
A pixel has no size until you pick a DPI
There is no fixed answer to “how many inches is 300 pixels”. At 96 DPI it is 3.125 inches, at 300 DPI it is one inch, and both are correct. Every number on this page names the DPI it was worked out at, because a length printed without one is a measurement of nothing.
There is no file here
This tool takes numbers and does arithmetic on them in your browser. Nothing is uploaded, nothing is stored and no account is needed, because there is nothing to upload in the first place. To change the DPI tag on an actual image, or to measure something on one, our DPI Converter and Pixel Ruler do that locally too.
How it works
The sum is pixels divided by DPI
DPI means dots per inch, so the number of inches is simply the pixel count divided by it. 1920 pixels at 96 DPI is 20 inches; the same 1920 pixels at 300 DPI is 6.4 inches. Centimetres, millimetres, points and picas are that inch figure multiplied by 2.54, 25.4, 72 and 6 in turn, which is why the table on this page moves together when you change one field.
Which DPI to type
The DPI belongs to the destination, not to the file. Print work is usually 300, draft and large-format work often 150, and office printers sit somewhere between. 96 is the CSS reference pixel, which is what a browser means by a pixel, and 72 is the old PostScript point that still turns up in design software. The presets carry these with a note on each, so the choice is visible rather than assumed.
Going back to pixels shows what the rounding cost
Ask for 8.5 inches at 300 DPI and the answer is exactly 2550 pixels, which is clean. Ask for 8.5 centimetres at the same density and it is 1003.94 pixels, and you cannot have a fraction of a pixel. This page prints the exact value, the whole-pixel count you would actually use, and the size that whole count really measures, so you can see the difference instead of assuming there is none.
A web page cannot read your screen density
Browsers expose a device pixel ratio, which is how many device pixels go into one CSS pixel. It is not a physical density: a phone and a large monitor can report the same ratio at wildly different real densities, and nothing available to a page closes that gap. So this tool asks you for the DPI rather than guessing one, and says what the reported ratio is and is not. For a screen you can measure, divide the horizontal resolution by the physical width in inches.