Change Image DPI: how it works
Print shops, publishers and some application forms ask for images at 300 DPI. DPI is just a label stored in the file that tells printers how large to print it; changing it doesn't add detail. This tool rewrites that label in JPG and PNG files directly, so the image itself isn't re-compressed at all.
If you need a specific printed size, switch to 'Resize to print size', enter the width in centimetres, millimetres or inches, and FileStripe calculates the pixels needed at your chosen DPI.
How to change the DPI of an image
- Add your images.
- Choose the DPI (300 is the usual print standard).
- Download. The note shows how large each image will print.
Features
- No re-compressionOnly the DPI field changes.
- Print size modeExact cm, mm or inches.
- JPG and PNGOther formats are saved as PNG.
- BatchMany images at once.
Frequently asked questions
Does changing DPI improve quality?
No. It only changes how large the image prints. A 600 × 600 pixel image is 2 × 2 inches at 300 DPI or about 8 × 8 inches at 72 DPI; it has the same detail either way.
How many pixels do I need for 300 DPI?
Multiply the print size in inches by 300. A 4 × 6 inch photo needs 1200 × 1800 pixels; an A4 page needs about 2480 × 3508.
Is the Change Image DPI free?
Yes. The Change Image DPI is completely free with no sign-up, no watermarks, no daily limits and no premium tier.
Are my files uploaded to a server?
No. FileStripe processes your files locally in your web browser using JavaScript. Nothing is uploaded, so the Change Image DPI is safe for private photos and confidential documents and even works offline once the page has loaded.
Does it work on iPhone and Android?
Yes. The Change Image DPI works in Safari, Chrome, Firefox, Edge and Samsung Internet on phones, tablets and computers. On a phone you can pick files from your photo library or files app and share the result straight to another app.
Last updated · Processing happens locally in your browser.