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Image DPI Converter

Change the DPI value written in a JPG or PNG file, for example to 300 for a print shop, and see how large the image will print. The pixels are not touched.

Upload Image to Change DPI

Drag and drop files here, or click to browse

Your images are processed in your browser and are not uploaded to Image York.
You retain full ownership of your images. Image York does not store or claim rights. View License

What DPI really controls

A digital image is a grid of pixels. DPI (dots per inch, also called PPI) is a number stored in the file that tells printing and layout software how many of those pixels to place in each inch of paper. It does not change how the image looks on a screen, and it does not add or remove detail.

The useful calculation is print size = pixels divided by DPI. A 3000 x 2000 pixel photo at 300 DPI prints at 10 x 6.67 inches. Set the same file to 150 DPI and it prints at 20 x 13.33 inches, with each pixel twice as large on paper. The tool shows this calculation for your image as you move the slider.

How the file is changed

  • JPG: the density fields in the JFIF header are set to your value in dots per inch. If the file has no JFIF header (common with camera photos), a standard one is added. If an EXIF block already contains resolution fields, those are updated too, so programs that read either place see the same value.
  • PNG: any existing pHYs chunk is replaced with one holding your value, stored in pixels per metre as the PNG format requires.

The compressed image data is copied byte for byte, so dimensions and quality stay exactly the same. Only these header fields change. Other formats show an error; convert them to JPG or PNG first.

When a print shop asks for 300 DPI

Usually they mean the image must have enough pixels to print sharply at the size you ordered, at around 300 pixels per inch. Changing the number in the header satisfies software that checks the field, but it cannot create detail. Check the print size the tool shows: if a 1200 x 800 photo at 300 DPI comes to only 4 x 2.67 inches and you ordered an A4 print, the image is too small for that size, whatever the DPI field says.

Enlarging with the Image Resizer gives more pixels but not more detail. The honest options are a larger original or a smaller print.

Common values

DPITypical use
72 or 96Screen-only images; the value is ignored by browsers
150Large posters viewed from a distance
300Photo prints, brochures and most commercial printing
600Line art and fine text scans

Where the processing happens

The header is rewritten in your browser. The file is not uploaded.

Questions about this tool

Will changing DPI make my image sharper?

No. It only changes the print-size instruction. Sharpness depends on how many pixels the image has.

Why does my app still show the old DPI?

Some programs read resolution from a Photoshop-specific block that this tool does not edit, or cache file details. Re-open the downloaded copy, not the original.

My print shop wants a 300 DPI file. How do I change it?

Open the JPG or PNG, set the slider to 300 and download. The DPI value in the file changes and the pixels stay exactly the same. Check the print size shown, because that tells you how large the photo will print sharply.

The tool says my photo prints at only 4 x 3 inches at 300 DPI. Can I print it larger?

Not sharply. The photo does not have enough pixels for a bigger print at 300 DPI. Use a larger original, accept a smaller print, or lower the DPI and accept some softness.

Will changing the DPI change the file size or quality?

No. Only a small field in the file header changes. Width, height and quality stay exactly as they were.

My image is a WebP. Can I change its DPI here?

No. Only JPG and PNG are supported. Convert the image first, for example with WebP to PNG, then set the DPI.

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