Tool · Density
DPI
converter.
Drop a JPEG or a PNG, pick the density, take the file back. Milliseconds, no upload, no re-encoding: the pixels never move.
Density to write
What this tool does, and what it does not
In short
- It changes a tag, two bytes in the file header. It touches no pixel and re-encodes nothing, so there is no loss.
- It does not make the image better. Density holds no detail; it only decides the print size.
- It does not enlarge it. If your pixels fall short of the size you want, they have to be built: that is the workshop's job.
Why going from 72 to 300 changes nothing
An image file holds a grid of pixels and, somewhere in the header, a line saying "when printing, pack them this many per inch". That line is the DPI. It occupies two bytes.
Rewriting it divides the announced print size by 4.17, since the same pixels are now packed four times tighter. The image gained nothing and lost nothing: it simply started telling the truth about what it can print.
| Before | After | |
|---|---|---|
| Pixels | 1920 × 1080 | 1920 × 1080 |
| Tag | 72 DPI | 300 DPI |
| Announced size | 26.7 × 15.0 in | 6.4 × 3.6 in |
| Detail held | identical | identical |
A printer asking for "300 DPI" never means that tag. They mean enough pixels for the size ordered. The full guide.
Three differences from other online converters
Your file does not leave
Most of them upload the image, process it on a server and hand it back. Here everything happens in the tab: it is faster, and the question of what becomes of your file never arises.
No re-encoding
Many tools reopen the JPEG and save it again, which recompresses it and costs quality for an operation that should have touched two bytes. The file downloaded here weighs exactly what the one you dropped weighed.
Both headers are written
A JPEG declares its density in two places, JFIF and EXIF, and software does not read the same one: Windows looks at the first, Photoshop at the second. Writing only one gives a file that reads 300 here and 72 elsewhere.
Short on pixels?
The tag will not build them. The workshop enlarges the image with a neural network, inside your browser, and writes the file in a size print shops sell. Its interface is in French for now.
See also: check an image, DPI calculator, print size by megapixels.