How to change the DPI of an image
Print shops, publishers and forms often ask for 300 DPI. Setting it takes seconds and doesn't touch image quality — but it's worth knowing when you also need more pixels.
Change DPI in your browser
- Open the DPI changer and drop one or more JPG or PNG files.
- Check the current DPI and print size shown for each image.
- Pick 300 (or type any value) — the new print size updates instantly.
- Download. Only the resolution tag changes, so the pixels are identical.
Check an image's current DPI
- Windows: right-click the file → Properties → Details → Horizontal resolution.
- Mac: open the image in Preview → Tools → Show Inspector → Image DPI.
- Any device: drop it into the DPI changer — the current value is shown before you change anything.
Set the DPI, or resize to a print size?
If you only need the file to report 300 DPI, change the DPI — nothing else happens to the image. If it has to print at a specific size, such as 3.5 × 4.5 cm or 4 × 6 inches, resize it to that print size instead: that sets both the pixel dimensions and the DPI.
When a photo doesn't have enough pixels, raising the DPI makes it print smaller, not sharper. Divide the pixel width by 300 to find the largest sharp print width in inches.
Tools used in this guide
Related guides
How to change the DPI of an image — FAQ
Use a tool that edits only the resolution tag. This one rewrites the JPG or PNG header without re-encoding, so the pixels — and the quality — stay exactly the same.