Pixels to inches: understanding DPI
Pixels have no fixed physical size until you know how many fit in an inch. This guide explains DPI in plain terms.
What is the On-Screen Ruler?
This tool converts a pixel length to inches, centimetres and millimetres using the DPI value you give it. It assumes 96 DPI by default, which is a common screen convention, but real screens vary, so treat on-screen inches as an estimate, not a physical measurement.
How to use it
- Enter a length in pixels.
- Enter the DPI, or leave the default 96.
- Read the inch and centimetre equivalents.
Worked example
192 pixels at 96 DPI equals 2.00 inches, or 5.08 centimetres.
How do I convert pixels to inches?
Divide the pixel count by the DPI: pixels divided by dots per inch gives inches.
Frequently asked questions
Why 96 DPI?
It is the long-standing default screen DPI used by many systems, so it is a useful common reference.
Will this match a physical ruler on my screen?
Not exactly, because real screen DPI varies by device and zoom level.