Change Image DPI

Free Online DPI Changer for Images

DPI (dots per inch) is a piece of metadata stored inside an image file that tells printers and some software how large the image should appear when printed, based on its pixel dimensions. It's a common requirement for stock photo submissions, print services, and design templates that ask for images at "300 DPI" - even though the pixel content of the file doesn't need to change at all. LovePDFImg's Change DPI tool updates this metadata directly.

For JPG files, the DPI is stored in the JFIF header near the start of the file; for PNG files, it's stored in a chunk called pHYs. This tool reads your image's existing header, updates (or adds) the relevant DPI fields, and recalculates any checksums needed for PNG chunks - all without touching the actual pixel data. The result is the same image, at the same pixel dimensions, with new resolution metadata. Everything happens locally in your browser.

This is a quick fix when a printing service, stock photo platform, or publishing template rejects an image for having the "wrong" DPI, even though the actual pixel dimensions are already sufficient for the intended print size.

Key Features

• Metadata-only edit: Changes DPI without touching pixel data.
• Common DPI presets: Quick options like 72, 96, 150, and 300 DPI.
• Supports JPG and PNG: Handles both common header formats correctly.
• No quality loss: The visible image is completely unchanged.
• Browser-based processing: Your file never leaves your device.
• Free and unlimited: No account, no daily cap, no watermark.

Who Uses Change DPI?

Photographers: Set images to 300 DPI to meet stock photo platform or print lab submission requirements.

Designers: Fix DPI metadata on assets that a print vendor or template flags as incorrect.

Businesses: Prepare marketing materials or documents to meet a print shop's specified resolution metadata.

Students and researchers: Adjust image metadata to satisfy a journal or thesis submission's formatting guidelines.

Why Choose LovePDFImg to Change Image DPI?

Most tools that adjust DPI require a full photo editor like Photoshop, or a server-side conversion service. LovePDFImg edits the header metadata directly in your browser with no software installation and no upload. There's no account requirement, no daily cap, and the tool is completely free.

Technical Explanation: DPI vs Pixel Dimensions

DPI and pixel dimensions are two separate properties of an image file. Pixel dimensions (e.g., 3000×2000 pixels) determine the actual detail captured; DPI is simply a stored instruction for how large to print that pixel grid (a 3000-pixel-wide image at 300 DPI prints 10 inches wide, while the same file at 150 DPI prints 20 inches wide). Because DPI doesn't affect the pixel data at all, changing it has zero impact on how the image looks on a screen - screens display images at their native pixel resolution regardless of the embedded DPI value.

How to Change an Image's DPI

1. 1Upload your imageDrag and drop a JPG or PNG file, or click to browse.
2. 2Choose a DPI valuePick a common value like 72, 96, 150, or 300, or enter a custom number.
3. 3Click "Apply DPI"The tool updates the image's header metadata with the new DPI value.
4. 4Download your imageThe pixel content is unchanged - only the DPI metadata is updated.

Frequently Asked Questions