How to use Change Image DPI

Choose a JPEG, PNG or WebP image.
Enter the density and choose whether to keep pixels or resize to a print width.
Create the PNG copy and check its pixel size and density before printing.

Example: Change Image DPI

A local worked example using the inputs and settings below for change image dpi.

You add

Image: ["sample.png (348 bytes)"] Print density (DPI): "300" Change: "density" Print width in cm (resize mode): "10"

You get

Created 80 × 60 PNG at 300 DPI. sample-300dpi.png (80 × 60 pixels)

Options

Density mode: Changing density keeps pixel dimensions while writing the PNG pHYs value. A print application may ignore that metadata.
Print-width mode: Resizing to an entered width changes pixel count under the chosen density. More pixels do not recover detail absent from the original.

Supported inputs and limits

File sizeOne image up to 64 MiB

Working pixels24 megapixels

FormatsJPEG, PNG and WebP

One JPEG, PNG or WebP up to 64 MiB, 24 megapixels and 10,000 pixels per side. Density: 36–1,200 DPI. Entered width: 1–100 cm. Output is PNG, capped at 8 megapixels and 4,096 pixels per side. Pixels per metre are rounded to an integer. Canvas re-encoding drops source metadata and may change colour decoding. Print apps can ignore density; resizing cannot recover detail.

Where your input is processed

This tool processes your input in this browser. Your text and files are not uploaded to UseFreeTools. Check this tool's limits for anything it may save on your device.

Check physical size in the print application

PNG stores rounded pixels per metre rather than the exact decimal DPI label. Keep the pixel dimensions and intended print width with the file. Inspect scale and margins before printing because the destination controls physical placement.

Questions about Change Image DPI

Does changing DPI improve a small image?

The density-only choice changes the suggested printed size. It keeps the same number of pixels, so it adds no detail.

Why is the stored value slightly different?

PNG stores whole pixels per metre rather than DPI. Converting between these units introduces a small rounding difference.

Can I retain a JPEG file?

This page exports PNG so the print-density record can be written and checked. The original file remains yours to keep.

Project manager: Tony Hines · Content updated 4 October 2026 · Report a problem