DPI Converter
Change the DPI of your images instantly. Supports JPEG, PNG, and BMP. All processing happens in your browser — no uploads, no account, no server.
Why Use Our DPI Converter?
100% Private
All processing happens locally in your browser. Your images never leave your device.
Instant Results
No server round-trips. DPI metadata is modified in milliseconds.
Bulk Conversion
Convert multiple images at once. Set your DPI once and apply to all files.
Multi-Format
Supports JPEG, PNG, and BMP formats with proper metadata handling.
Free Forever
No sign-up, no watermark, no limits. Completely free to use.
Pixel-Perfect
Only DPI metadata changes. Pixel dimensions stay exactly the same.
How DPI Conversion Works
DPI (dots per inch) is a metadata value stored inside image files. It tells printers and software how many pixels should be printed per inch of physical paper. Changing DPI does not alter the actual pixel data of your image. It only updates the density information in the file header.
For example, a 3000 x 2000 pixel image at 72 DPI would print at 41.6 x 27.7 inches. The same image at 300 DPI would print at 10 x 6.6 inches. The pixel count stays 3000 x 2000 in both cases.
Our tool modifies the JFIF density fields for JPEG files, the pHYs chunk for PNG files, and the biXPelsPerMeter and biYPelsPerMeter fields for BMP files. This ensures compatibility with professional printing software, Adobe Photoshop, InDesign, and other design tools that read DPI metadata.
Frequently Asked Questions
Does changing DPI affect image quality?
No. DPI is purely metadata. The actual pixel data of your image remains untouched. Only the density value in the file header changes, which affects how the image is sized when printed.
What DPI should I use for printing?
For professional printing, 300 DPI is the standard. For newspapers or large format prints, 150 to 200 DPI is often sufficient. For web and screen use, 72 DPI is the traditional default.
Are my images uploaded to a server?
No. All processing happens entirely in your browser using JavaScript. Your images never leave your device, ensuring complete privacy and security.
Can I convert multiple images at once?
Yes. Select or drag multiple files at once, choose your DPI value, and click Convert. Each image will be processed independently and available for individual download.
What is the difference between DPI and PPI?
DPI (dots per inch) refers to printed output resolution, while PPI (pixels per inch) refers to digital display resolution. In practice, most software uses these terms interchangeably for image metadata. Our tool sets the value that printers and design software expect.
What image formats are supported?
We support JPEG, PNG, and BMP. Each format stores DPI metadata differently, and our tool handles the specific byte-level modifications required for each format correctly.
Free, Private, and Always Available
This tool is part of the MergeImg free toolkit — built for designers and photographers who need fast, no-nonsense image processing. No sign-up, no file size limit, no watermarks.