Change DPI of Image: what it does
Printers, print shops, Etsy printable buyers, KDP and many online forms ask for “300 DPI”. DPI (dots per inch) is only a number stored in the image file that tells a printer how big to print it: a 3000 × 2400 pixel photo at 300 DPI prints at 10 × 8 inches, and the same photo at 72 DPI would print at 41 × 33 inches. Changing it does not add or remove any detail. Many online tools re-save your image to change it, which costs quality. This one rewrites only the resolution fields in the file (the JFIF header, EXIF and Photoshop info in a JPG, the pHYs chunk in a PNG) and copies the picture data byte for byte, so the image is exactly as sharp as before. Drop as many JPG or PNG files as you like, pick 300 DPI or type any value, and see each image’s old DPI and its print size in inches and centimetres. The print size calculator tells you how many pixels you need for a print size, and whether your image has them.
How to use it
- Drop one or more JPG or PNG images into the box, or tap to choose them.
- Pick the DPI you need (300 for most printing), or type any number. Each image shows its old DPI and the print size at the new one.
- Download each image, or all of them as one ZIP. The pixels and quality are exactly the same: only the DPI value in the file changes.
- Use the print size calculator to check that an image has enough pixels for the size you want to print.
Tips
- If an image is too small for a print, raising the DPI makes the print smaller, not sharper. Check the print size in the list: for a sharp 8 × 10 inch print at 300 DPI you need 2400 × 3000 pixels.
- Screens ignore DPI completely. A website, Instagram or WhatsApp shows the same image at the same size whatever its DPI.
- Photoshop and Word read the new DPI, so a 300 DPI image is placed at its real print size.
- For Etsy printables, set 300 DPI on the final file and say the print size in the listing (for example “prints at 8 × 10 in”).
- Some online forms ask for a DPI and a maximum file size at once. Use the photo resizer for online forms, which sets both.
- WebP and HEIC files have no DPI setting. Convert them to JPG or PNG first, then set the DPI here.
Frequently asked questions
Does changing the DPI reduce the quality?
No. Only the DPI number in the file’s header is changed. The picture data is copied byte for byte, so the pixels are identical: you can check that the width and height in pixels are the same before and after.
How do I make an image 300 DPI?
Drop it in the box above with 300 selected and download it. The file now says 300 DPI, which Photoshop, Word, Windows (Properties → Details) and print software read. If the print size shown is smaller than you need, you need an image with more pixels.
What is the difference between DPI and pixels?
Pixels are the real detail in the image (for example 3000 × 2000). DPI only says how many of those pixels go into one printed inch. 3000 pixels at 300 DPI prints 10 inches wide; at 150 DPI the same pixels print 20 inches wide, with each pixel twice as big.
Why does my phone photo say 72 DPI?
72 is a default many phones and apps write without meaning anything by it. A 4000 × 3000 phone photo set to 300 DPI prints sharply at about 13 × 10 inches.
Are my images uploaded?
No. The files are read and rewritten by your browser on your device. Nothing is sent to our servers.