Image Tools
Image DPI Checker
Check the DPI (dots per inch) declared in a JPG or PNG image and see its print size in inches and centimetres. Reads the file's JFIF, EXIF or PNG resolution data right in your browser.
How to check the DPI of an image
- Choose a JPG or PNG file.
- The tool reads the resolution stored in the file — JFIF or EXIF data in a JPG, the pHYs chunk in a PNG — and shows the DPI it finds.
- See the print size that DPI implies, in inches and centimetres, based on the pixel dimensions.
- If no DPI is stored, go by the pixels: divide them by 300 for the largest sharp print.
Where DPI lives inside an image file
DPI is just a number written into the file's metadata, and different formats keep it in different places. JPGs can carry it in the JFIF header, which records a density and a unit (per inch or per centimetre), or in EXIF fields called XResolution and YResolution. PNG stores it in a pHYs chunk measured in pixels per metre, so 300 DPI appears there as 11,811. The checker reads all three and converts them to DPI.
Changing that number doesn't change the picture. Setting a 72 DPI photo to 300 DPI in an editor, without resampling, only changes the print size it suggests: the same 3000 × 2000 pixels print at 10 × 6.7 inches instead of 41.7 × 27.8 inches.
Pixels needed for common print sizes
| Print size | At 300 DPI | At 150 DPI |
|---|---|---|
| 4 × 6 in (10 × 15 cm) | 1200 × 1800 | 600 × 900 |
| 5 × 7 in (13 × 18 cm) | 1500 × 2100 | 750 × 1050 |
| 8 × 10 in (20 × 25 cm) | 2400 × 3000 | 1200 × 1500 |
| A4 (210 × 297 mm) | 2480 × 3508 | 1240 × 1754 |
| A3 (297 × 420 mm) | 3508 × 4961 | 1754 × 2480 |
| 18 × 24 in poster | 5400 × 7200 | 2700 × 3600 |
Pixel dimensions for sharp prints at 300 DPI, and at the more forgiving 150 DPI that's fine for posters viewed from a distance.
When someone asks for a 300 DPI image
Print shops, publishers and application portals that ask for 300 DPI almost always mean enough pixels to print the requested size sharply. Check the pixel dimensions against the table above rather than the DPI tag: a 4000 × 3000 photo tagged 72 DPI prints a perfect 13.3 × 10 inch picture at 300 DPI once the tag is changed, while a 600 × 400 image tagged 300 DPI is still only good for a 2 × 1.3 inch print.
Screens ignore DPI entirely. On a website or in an app only the pixel dimensions matter, which is why many images — screenshots and web downloads especially — store no DPI at all.
Frequently asked questions
What is DPI?
DPI (dots per inch) is the print resolution — how many pixels print per inch. It only matters for printing; screens use pixel size.
Why does my image show no DPI?
Many images don't store a DPI value. Viewers then assume 72 or 96 DPI. The pixel dimensions still determine print quality.
What DPI is good for printing?
300 DPI is the standard for sharp prints. Divide an image's pixel width by 300 to get the largest good print width in inches.
Is my image uploaded?
No. The file is read locally in your browser.
Is DPI the same as PPI?
Strictly, PPI (pixels per inch) describes an image and DPI (dots per inch) describes a printer's ink dots. In everyday use the two terms are interchangeable, and the value stored in an image file is really PPI.
Which DPI should I use when scanning?
300 DPI for photos and documents you may print, 150–200 DPI for documents that only need to be read on screen, and 600 DPI or more only for small originals such as stamps or slides that you plan to enlarge.
Why does my phone photo show 72 DPI?
Phones write 72 DPI as a default because the number has no effect on screen. It says nothing about quality: a 12-megapixel photo tagged 72 DPI still has enough pixels for a sharp 13 × 10 inch print.
Can this tool change the DPI?
No — it only reads it. Because DPI is a label rather than a property of the pixels, you rarely need to change it: give the printer the pixel dimensions it needs and set the print size in the print dialog.
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