Change the DPI of an image

Change the DPI of a PNG or JPEG so it prints at the correct physical size, without resampling or altering a single pixel. This free online DPI converter lets you set the exact print resolution you need — 72, 150, 200, 300 DPI or any value up to 6000 — and download the same image with updated pixel-density metadata. For PNG a real pHYs chunk is written with a recomputed CRC-32; for JPEG the JFIF density is set in inches. Because everything runs 100% in your browser, your image is never uploaded to any server and processing is instant and completely private.

🔒 100% private — files never leave your device

Loading…

How to use

  1. Select or drop a PNG or JPEG image into the tool.
  2. Enter the DPI you want, for example 300. If a current DPI is stored in the file, it is shown automatically.
  3. Click Apply DPI to rewrite the print-resolution metadata locally in your browser.
  4. Download the same image with its new DPI — the pixels are untouched.

Frequently asked questions

Does changing the DPI resize or reduce the quality of my image?

No. This tool only changes the print-resolution tag, not the pixel dimensions or the image data. The picture looks identical on screen and loses no quality — it simply prints larger or smaller depending on the DPI you set.

Which file formats are supported?

PNG and JPEG (.png, .jpg, .jpeg). For PNG a pHYs chunk is inserted or replaced with a correctly recomputed CRC-32; for JPEG the JFIF APP0 density is set to inches, and a JFIF segment is added if the file does not already have one.

Is my image uploaded or stored anywhere?

No. The DPI metadata is rewritten entirely in your browser using JavaScript, so your file never leaves your device and nothing is sent to a server.

What DPI should I use for printing?

300 DPI is the standard for high-quality photo and document printing, 150 DPI is fine for larger posters viewed at a distance, and 72 DPI is typical for screen use. You can enter any value from 1 to 6000 DPI.

Why does the file size stay almost the same after changing the DPI?

Because only a few bytes of density metadata are rewritten and the actual pixels are left completely untouched, the file size barely changes — you are editing a print-size tag, not recompressing the image.

What if my image has no DPI information stored?

That is fine. The tool inserts a fresh pHYs chunk for PNG or a JFIF density segment for JPEG, so your chosen DPI is written even when the original file did not specify one.

About this tool

Free online DPI converter that runs 100% in your browser. Change a PNG or JPEG's DPI (72, 150, 300 DPI) without resampling pixels or uploading files.

Related tools