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Check and change image DPI
Choose a JPG or PNG. You see its DPI, pixels and printed size, and can save a copy with a new DPI.
Works on your device. Nothing is uploaded.
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What DPI in a photo means
DPI (dots per inch) is a number in the file's header that tells a printer how big to print the picture. It does not change the picture: a 600 × 600 pixel photo is the same at 72 DPI and at 300 DPI. It prints 2 inches wide at 300 DPI and about 8.3 inches wide at 72 DPI. On screen and in a form, sharpness depends on the number of pixels.
When a form asks for 200 or 300 DPI
Notices that say "scan at 200 DPI" mean the scanner setting: scanning a 3.5 × 4.5 cm photo at 200 DPI gives about 276 × 354 pixels. If your photo already has the right pixel size, setting the DPI number in its header is all that is left. Phone cameras usually save 72 DPI, and some apps save none.
How to change the DPI
- Choose the JPG or PNG.
- Type the new DPI; 200 and 300 are the usual ones. The tool shows how big the photo prints at that DPI.
- Tap Save with this DPI and download. Only the header changes, so the quality and the pixels stay the same, and the file grows by at most a few bytes.
Pixels for common printed sizes
| Printed size | At 200 DPI | At 300 DPI |
|---|---|---|
| 3.5 × 4.5 cm | 276 × 354 px | 413 × 531 px |
| 2 × 2 inch | 400 × 400 px | 600 × 600 px |
| 3 × 3 cm | 236 × 236 px | 354 × 354 px |
| 10 × 5 cm | 787 × 394 px | 1181 × 591 px |
To change the pixels as well, use the image resizer: it takes sizes in cm, mm or inches at the DPI you choose and saves that DPI in the file.
Questions people ask
- Does changing the DPI reduce quality?
- No. Only the DPI number in the header changes. The pixels and the picture data are copied as they are.
- How do I check the DPI of a photo?
- Choose it here: the DPI and the printed size show at once. If the file has no DPI saved, the tool says so; most programs then assume 72 or 96.
- What DPI should a passport size photo be?
- For printing, 300 DPI: a 3.5 × 4.5 cm photo is then 413 × 531 pixels. For online forms the pixels and KB in the notice matter more, and many notices ask for scanning at 200 DPI.
- Why does my computer still show 96 DPI?
- Some programs show their own screen setting instead of the file's DPI. This tool saves the DPI in the JFIF header and also updates the EXIF one when the photo has it, so programs that read either see the new number.
- Is my photo uploaded?
- No. The new copy is made by your own browser.