Updated July 9, 2026
The short answer
Windows: right-click the file, Properties, then the Details tab. Mac: open the image in Preview, then Tools, Show Inspector, or press Cmd+I. iPhone: Photos shows basic pixel dimensions in the edit view; for DPI specifically, a free EXIF viewer app is quicker.
How to check on Windows
Right-click the image file in File Explorer, choose Properties, then open the Details tab. Scroll to Horizontal resolution and Vertical resolution for DPI, and look further up the list for Width and Height in pixels.
How to check on Mac
Open the image in Preview by double-clicking the file, then go to Tools, Show Inspector, or press Cmd+I. The Image tab shows pixel dimensions and DPI, labeled there as resolution.
Verify what you found
Run the pixel dimensions you just checked through the DPI Calculator to see the actual DPI at any print size you have in mind.
How to check in Photoshop
Go to Image, then Image Size. Photoshop shows pixel dimensions and document resolution in the same dialog. Uncheck Resample and change the resolution field to see what print size those pixels produce at a given DPI, without adding or removing any pixel data.
How to know if an image is 300 DPI
If the Details tab on Windows or the Inspector on Mac shows 300 under horizontal and vertical resolution, the metadata says 300 DPI. Metadata is easy to change without adding a single pixel, though, so the real test is whether the pixel dimensions are actually large enough for the target print size.
Things to know before you check resolution
A DPI value stored in a file's metadata is a label, not a guarantee. Two images can both claim 300 DPI in their properties while one has plenty of pixels and the other does not, because resizing an image in an editor can leave the DPI field untouched while the pixel count changes underneath it.
FAQs
Is there a way to check the resolution of an image?
Yes. Windows: right-click, Properties, Details. Mac: open in Preview, press Cmd+I. Photoshop: Image, Image Size. A free EXIF viewer app works too.
How do I know if an image is 300 DPI?
Check the resolution field in the file properties or metadata, then confirm the pixel dimensions are large enough for your target print size at 300 DPI.
What size is a 1920 x 1080 image?
At 300 DPI, about 6.4 x 3.6 inches. At 150 DPI, about 12.8 x 7.2 inches. The Print Size Calculator gives the exact figure for any DPI.
Is 600 DPI the same as 600 PPI?
In workflow terms, yes. Both describe 600 units of detail per inch, and setting an image to 600 PPI for a 600 DPI printer lines the two up.
Related: the pixel count each print size needs, picking the right DPI for the job, and what large formats demand.