Change Image DPI

Change the DPI of a JPG or PNG

Print shops, stock sites and forms often ask for a 300 DPI image. DPI (dots per inch) is a number stored in the file's metadata that tells software how big the picture should be when printed. This tool rewrites that value without touching a single pixel, so the image looks exactly the same and no quality is lost.

For JPG files it updates the JFIF density field, adding the header if it is missing, as well as the EXIF and Photoshop resolution tags that Windows, Photoshop and most editors read first. For PNG files it writes the pHYs chunk, which stores pixels per meter. Other formats such as WebP, BMP or HEIC are first converted losslessly to PNG so the DPI can be stored. All of it happens in your browser and the file is never uploaded.

DPI, pixels and print size

Print size equals pixel dimensions divided by DPI. A 3000 × 2000 px photo prints at 10 × 6.67 inches at 300 DPI, but at 41.7 × 27.8 inches at 72 DPI. The tool shows this calculation under the controls so you can check that you have enough pixels for the size you want. Setting a higher DPI does not add detail; it only makes the printed picture smaller.

Common DPI values

Use 72 or 96 DPI for screens, 150 DPI for draft prints and large posters viewed from a distance, 300 DPI for photo prints and documents, and 600 DPI or more for fine line art and scans. You can process several images at once: one image downloads directly, several arrive in a single ZIP, and each file name includes the DPI, for example photo-300dpi.jpg.

Changing DPI is different from resizing. If a print service needs a specific pixel size, for example 3600 × 2400 px for a 12 × 8 inch print at 300 DPI, first resize the image and then set the DPI here. Keep in mind that some websites and messaging apps strip metadata on upload, so send the file as a document or by email when the DPI value must survive.