What the result means
- A number such as 72, 144 or 300: the value stored in the file.
- "not set": the file has no DPI value. Some programs then assume 72 or 96.
- Two different numbers (for example 300 x 72): the file has a different value for width and height. This is rare, and setting one DPI fixes it.
Other ways to check
On a Mac, open the image in Preview, choose Tools, then Show Inspector. The DPI is listed there.
On Windows, right-click the file, choose Properties and open the Details tab. Look under Image for horizontal and vertical resolution.
On a phone, most gallery apps do not show DPI. Add the photo here instead.
Why the DPI of a photo is often meaningless
A camera or phone writes a default value, often 72 or 300, whatever the pixel count. The size you can print depends on the pixels. A 4000 by 3000 pixel photo prints well at 13 by 10 inches at 300 DPI, even if the file says 72.
Questions
- Does checking change my file?
- No. The file is only read in your browser. It changes only if you press Download.
- Why does a screenshot say 144 DPI?
- Retina Macs capture twice as many pixels per inch as older screens, and the file notes this as 144 DPI.
- Can I check many files?
- Yes. Add them all and each row shows its own values.