Image DPI
Read and set the DPI of an image without resampling.
Overview
The Image DPI tool reads and updates the dots-per-inch (DPI) metadata stored inside an image without touching a single pixel. Upload a file, see the current horizontal and vertical DPI, type a new value and the tool returns a re-encoded copy with the metadata field updated.
Print designers, magazine production teams and anyone preparing files for a CMYK workflow use this when a printer asks for "300 DPI" but their source files are tagged at 72. It is also the right tool for fixing 96-DPI screenshots that need to land in a Word or InDesign document at the correct physical size.
How it works
DPI is purely a metadata flag — it tells software the intended physical size at which the pixels should be printed or displayed, without changing the pixel data at all. For JPEG, DPI lives in the JFIF segment (X density, Y density, units). For PNG it sits in the pHYs ancillary chunk (pixels per unit X, pixels per unit Y). For TIFF it lives in the XResolution and YResolution tags.
The tool rewrites whichever container the input uses and recomputes any required length or CRC fields. Image data, palette, alpha, and EXIF blocks are preserved verbatim, so quality is identical and only the printed/displayed size hint changes.
Examples
Before: scan.jpg, 2400x3000 pixels, tagged at 72 DPI → prints 33"x42"
After: scan.jpg, 2400x3000 pixels, tagged at 300 DPI → prints 8"x10"
Before: screenshot.png, 1920x1080, tagged at 96 DPI
After: screenshot.png, 1920x1080, tagged at 150 DPI (Word default)
Before: artwork.tiff with no DPI tag
After: artwork.tiff with 300x300 DPI for press output
FAQ
Will changing DPI change image quality?
No. The pixel data is untouched — only the metadata flag changes. The physical print size changes, but on-screen everything looks identical.
Does my browser care about DPI?
Browsers ignore the embedded DPI flag and lay images out by pixel count. DPI only matters for print software and image-editing tools.
What's the difference between DPI and PPI?
PPI (pixels per inch) describes screen density and is set by the display. DPI (dots per inch) describes a printed image's intended size. The metadata flag uses DPI but is functionally equivalent for raster files.
Can I resample to a target DPI instead?
Yes — use the Image Resizer to change the actual pixel count, then update the DPI flag here. Resampling adds or removes pixels; this tool only rewrites the metadata.
Why does my printer report a different DPI?
The printer driver may override the file's flag based on the page setup. Match the DPI of the file to the driver's target output size to avoid surprises.