Image DPI Checker
Check the DPI stored in a photo, see its pixel dimensions and print sizes, and change the DPI tag for printing. Your image stays on your device.
Drag & Drop images to check DPI
Supports JPG, PNG, WEBP, TIFF, BMP, HEIC
Your image is read in your browser and is not uploaded
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This image DPI checker reads the DPI value stored inside a photo, together with its pixel dimensions, and works out how large it will print. DPI (dots per inch) only matters for printing: it tells a printer how closely to pack the image's pixels onto paper. On a screen it changes nothing, because each image pixel is simply shown as a screen pixel. Mixing up resolution in pixels with DPI is the most common mistake when preparing an image for print.
How to Check the DPI of an Image
There are four quick ways to find the DPI of a photo, and they all read the same stored value.
- Online: drop the file into the checker on this page. It shows the DPI, the pixel size and the print size, and tells you whether a DPI tag was actually present.
- Windows: right-click the file, choose Properties, then the Details tab. Look for Horizontal resolution and Vertical resolution.
- Mac: open the image in Preview, then choose Tools and Show Inspector. The General tab lists Image DPI.
- Photoshop: choose Image, then Image Size. The Resolution field is the DPI. Untick Resample if you want to change it without altering the pixels.
DPI and Print Size
Print size is the pixel dimension divided by the DPI. The same image can therefore print large and soft or small and sharp, and the DPI tag only records which of those was intended.
| Image size in pixels | At 300 DPI | At 150 DPI |
|---|---|---|
| 1200 × 1800 | 4 × 6 in | 8 × 12 in |
| 2100 × 1500 | 7 × 5 in | 14 × 10 in |
| 2400 × 3000 | 8 × 10 in | 16 × 20 in |
| 3600 × 5400 | 12 × 18 in | 24 × 36 in |
- 300 DPI: sharp quality for photos, brochures and anything viewed up close.
- 150 DPI: acceptable for posters and banners viewed from a few feet away.
Changing the DPI of an Image
Some print shops and submission forms reject a file unless its DPI tag reads 300. If the image already has enough pixels for the print size, only the tag needs to change. The Change and Export option rewrites the DPI value in a JPG or PNG and leaves every pixel as it was, so nothing is recompressed. If the image does not have enough pixels, changing the tag will not help, and you need a larger original. To change the pixel dimensions themselves, use the Image Resizer, and to see everything else stored in a photo, the Photo Metadata Viewer.
DPI and PPI Are Not the Same Thing
In everyday use, and in most software, DPI and PPI are treated as the same word, and this checker reports the stored value as DPI because that is what people search for. There is a real distinction, though. PPI (pixels per inch) describes the pixel density of a digital image. DPI (dots per inch) describes the physical dots of ink or toner a printer lays down, and a printer often uses several dots to reproduce the colour of one pixel. The number stored in a JPG or TIFF file is, strictly speaking, a PPI value.
Where the 300 DPI Rule Comes From
An offset press does not print a photo as continuous tone. It breaks the image into a halftone screen, a grid of ink dots of varying size that the eye blends back into smooth tones. The density of that screen is measured in lines per inch (lpi), and a typical magazine or brochure uses a screen of about 150 lpi. Long-standing prepress convention is to supply images at about twice the screen ruling so that fine detail survives, and twice 150 is 300. The figure is a consequence of how halftone printing works, not an arbitrary round number.
Frequently Asked Questions
How do I check the DPI of an image?
Drop the image into the checker above and it reads the DPI value stored in the file. On Windows you can also right-click the file, choose Properties and open the Details tab, which lists horizontal and vertical resolution. On a Mac, open the image in Preview and choose Tools, then Show Inspector.
What DPI do I need to print a photo?
300 DPI is the standard for prints viewed up close, such as photos and brochures. 150 DPI is acceptable for posters and banners seen from a few feet away. Divide the pixel width by the DPI to get the print width in inches: 3000 pixels at 300 DPI is 10 inches.
Does changing the DPI value change my image quality?
No. DPI is a tag that tells a printer how to space the existing pixels. It adds and removes nothing. A 3000 × 2000 pixel image is the same image whether it is tagged 72 DPI or 300 DPI. Only resizing, which changes the number of pixels, affects quality.
Why does my image say 72 DPI?
72 DPI is a default left over from early Mac displays, and many cameras, phones and web tools still write it. It has no effect on a screen, which shows images pixel for pixel. If a file has no DPI tag at all, this checker reports 72 and says that no tag was found.
Is DPI the same thing as PPI?
Not technically. PPI (pixels per inch) describes the pixel density of a digital image, while DPI (dots per inch) refers to the ink or toner dots a printer lays down. The two are used interchangeably in everyday speech, and the number stored in an image file is strictly a PPI value.
Where does the 300 DPI rule come from?
From halftone printing. A commercial press prints photos through a screen of about 150 lines per inch, and prepress convention is to supply an image at about twice the screen ruling. Two times 150 is 300.