Change Image DPI
Set a JPG or PNG to 300 DPI (or any DPI) without changing a single pixel.
Drop JPG or PNG images
Other formats are converted to PNG
Files are processed on this device. Nothing is uploaded.
How to use Change Image DPI
- Drop one or more JPG or PNG images. Each file shows the DPI it stores now.
- Choose the DPI you need, usually 300 for print and application forms.
- Select Change DPI and download. Each result shows the size it will print at.
What DPI really changes
DPI (dots per inch) is a number stored inside an image file that tells printers and layout programs how large to print it. It does not change the pixels: a 3000 × 2400 image is 10 × 8 inches at 300 DPI and 41.7 × 33.3 inches at 72 DPI, with exactly the same detail. Many forms and print shops still ask for “300 DPI”, and this is usually what they check.
This tool rewrites only that number, so there is no re-compression and no quality loss. In a JPG it updates the JFIF density (adding the header if missing) and also the EXIF resolution tags when present, because some programs, including Photoshop, read those first. In a PNG it writes the standard pHYs chunk. Other formats such as WebP and HEIC have no standard DPI field, so they are saved as lossless PNG first.
If you need more detail for a large print, raising the DPI number does not help: you need more pixels. For a print of W × H inches at 300 DPI you need W × 300 by H × 300 pixels; the print size shown for each file tells you whether your image is big enough.
Example
A 1800 × 1200 JPG stored at 72 DPI opens in Word or InDesign at 25 × 16.7 inches. Set to 300 DPI, the same file places at 6 × 4 inches — a standard photo print — and its size in bytes changes by only a few bytes.
Frequently asked questions
How do I change an image to 300 DPI?
Drop the JPG or PNG, choose 300 DPI and select Change DPI. The pixels stay the same; only the stored print resolution changes.
Does changing DPI reduce quality?
No. Only a number in the file header changes; the image data is untouched. That is why the file size changes by just a few bytes.
How can I check the DPI of an image?
Drop it here: each file shows the DPI it currently stores, and where that value comes from (JFIF, EXIF or pHYs). “No DPI stored” means programs fall back to their own default, usually 72 or 96.
Will 300 DPI make my photo print sharper?
Only if it has enough pixels. A photo prints sharp at a size of pixels ÷ 300 inches. To print larger and still sharp you need a bigger original, not a higher DPI number.
Can I change the DPI of several images at once?
Yes. Add as many as you like and download them one by one or all together as a ZIP.
Are my images uploaded?
No. The files are edited in your browser and never leave your device.
Limitations
- Only JPG and PNG can store DPI; other formats are converted to PNG.
- Pixels are never added or removed (use Resize Image for that).
- A few programs ignore stored DPI and use their own default.
Guides for this tool
- What 300 DPI Really Means (and How to Change It)DPI does not change an image’s pixels: it tells printers how big to print it. What 300 DPI means, the pixels you need for each print size, and how to set it.
- Passport Photo Size by Country (2026): US, UK, EU, CanadaOfficial passport photo sizes and head heights for the US (2×2 in), UK and Schengen (35×45 mm), Canada (50×70 mm) and Australia, in mm and pixels, plus digital rules.
- How to Resize a Signature to 10–20 KB (and Why It Fails)Forms ask for a signature of 10–20 KB, but a 140 × 60 px signature is only 3–6 KB even at full quality. We measured it. Here is what actually works, step by step.
Last reviewed November 9, 2026. How we build and test tools.