Change Image DPI: Set 300 DPI for Print Online
Set the DPI stored in a JPG or PNG for print. The density fields are rewritten without touching the pixels.
DPI does not change how many pixels an image has. It tells print software how large to render them. Metadata mode rewrites the JFIF density fields in a JPG or the pHYs chunk in a PNG and leaves the encoded image alone, so nothing is re-compressed. Print-size mode is there for the other case: when the pixel count itself has to change so a given physical width lands at your chosen DPI.
How to Use It
- Upload your image and wait for the local preview to load.
- Adjust the settings: Pick metadata or print-size mode, set the target DPI, and for print size give the physical width and unit.
- Download the result: Download the processed file directly to your device.
Controls and Options
Use 300 DPI for print and 72 for screen; switch to print-size mode only when the pixel count itself has to change.
Formats and Output
Input: JPG, PNG. Output: the same format in metadata mode, or JPG/PNG when resampling. WebP carries no standard density field.
Frequently Asked Questions
Does changing DPI make my image sharper?
No. In metadata mode the pixels are identical before and after. Only the density tag changes, which tells print software how big to render them. To gain real detail you need more pixels, which is what an upscaler is for.
Why does the file size stay the same?
Because metadata mode does not decode or re-encode the image. For a JPG the JFIF density bytes are overwritten in place; for a PNG a 21-byte pHYs chunk is written. That is also why there is no second lossy pass.
When should I use print-size mode?
When the pixel count is wrong for the physical size you need. Ask for a 6-inch wide print at 300 DPI and the image is resampled to 1800 pixels wide, then tagged at 300 DPI.
Which formats are supported?
JPG and PNG, because those are the formats with a standard density field. WebP has no equivalent, so convert it first or use print-size mode with a JPG or PNG output.
Is my image uploaded anywhere?
Supported image content is not uploaded for processing. Reading, retagging, and export run in your browser; site analytics and the assistant are separate.