How to change DPI
- Add one or more JPG or PNG images. Each one shows its current DPI and the size it would print at.
- Tap the DPI you need, usually 300 for print and forms, or type your own.
- Press Change DPI and download. Several images come as one ZIP.
What DPI actually is
A digital photo is made of pixels; it has no size in centimetres on its own. DPI (dots per inch) is a note stored inside the file that says how many of those pixels should go into one inch when it is printed. A 1200 × 1800 pixel photo is 4 × 6 inches at 300 DPI, or 16.7 × 25 inches at 72 DPI. Same photo, same quality on screen, different print size.
So changing DPI does not make a blurry photo sharper. It changes how big it prints. To add real detail you need a bigger original.
Why forms and printers ask for it
- Some application portals check the DPI value of a photo or signature and reject files marked 72 or 96 DPI, even when the pixel size is right.
- Print shops and photo labs use the DPI to decide the print size. A file at 300 DPI prints at the size you expect.
- Publishers and printers often want 300 DPI for book covers, posters and visiting cards.
Need an exact size in cm too?
If the instruction says something like “3.5 × 4.5 cm at 300 DPI”, open More options and type the width and height in cm. The photo is resized to exactly 413 × 531 pixels and marked 300 DPI, trimming the edges if its shape is different. To also set a KB limit, use the Photo & Signature Resizer.
How to check the DPI on your computer
On Windows, right-click the file, choose Properties, then the Details tab, and look for Horizontal and Vertical resolution. On a Mac, open the image in Preview and choose Tools, then Show Inspector. FileFitly writes the new DPI in both the JFIF header and the EXIF data of a JPG, so both places show the same number.
Questions people ask
Does changing DPI reduce quality?
No. For JPG and PNG, the image data is copied exactly; only the DPI value changes. The KB stays almost the same.
Can I change DPI of many photos at once?
Yes. Add them together and download a ZIP.
What about HEIC, WebP or other formats?
They are converted to JPG at high quality and then given the DPI, because most forms want JPG anyway.
Is 300 DPI better than 72 DPI?
Not on screen; they look identical. It only changes the printed size, and some portals require 300.
Are my images uploaded?
No. Everything happens in your browser.