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Free DPI converter

Change image DPI online for free—72 to 600 or custom—then download PNG or JPEG. Local-first. No signup.

What is a free DPI converter?

A free DPI converter changes an image’s dots-per-inch (resolution) metadata for print or document briefs without altering pixel dimensions. Use this local-first tool to set 72–600 DPI or a custom value, then download PNG or JPEG—DPI alone does not add detail missing from the source.

Free DPI converter features

A local image DPI changer for print and document briefs.

  • Presets and custom DPI

    Pick 72, 96, 150, 200, 300, or 600 DPI, or enter a custom value.

  • Pixels unchanged

    Updates metadata only—no forced resample or upscale.

  • Print size readout

    See approximate inches at the selected DPI from current pixel size.

  • PNG or JPEG download

    Export with DPI tags and no watermark.

How to change image DPI online

From upload to a free DPI-tagged download.

  1. Add an image

    Drop a photo, scan, or illustration into the upload area.

  2. Choose the DPI

    Select a preset or enter a custom DPI your project requires.

  3. Download the copy

    Save PNG or JPEG with the new DPI metadata while keeping the original.

Tips for DPI conversion

Match the brief without false sharpness.
  • 01

    Start from enough pixels

    A 2400×3600 photo prints at 8×12 in at 300 DPI. Fewer pixels mean a smaller sharp print.

  • 02

    Use the inch readout

    Confirm the print size at your chosen DPI before you submit the file.

  • 03

    Prefer PNG for line art

    Drawings and text-heavy scans often survive PNG better than JPEG compression.

  • 04

    Need exactly 600 DPI?

    Use the dedicated 600 DPI converter when the brief only accepts that value.

Great for

When a free DPI converter helps.

  • Print submissions

    Match 150, 300, or 600 DPI requirements from a shop or school.

  • Document packs

    Give several images one consistent DPI label before handoff.

  • Quick checks

    See whether your pixel grid fits the intended print size.

Why change DPI here

Fast local resolution tagging.

  • Free

    Unlimited DPI changes with no signup.

  • Local-first

    Images stay in the browser for this tool.

  • Flexible DPI

    Presets plus custom values for uncommon briefs.

  • No watermark

    Clean PNG or JPEG downloads for submission.

Technical notes

How DPI is written into the file.
PNG
Inserts or replaces the pHYs chunk with pixels-per-meter for the chosen DPI.
JPEG
Patches the JFIF APP0 density fields (units = dots per inch).
Pixels
Canvas redraw keeps width and height; no resampling for DPI alone.
Privacy
Client-side only—no network upload.

Sources & References

Image resolution and PNG density references.
  • “The pHYs chunk specifies the intended pixel size or aspect ratio for display of the image.”
    — W3C Portable Network Graphics (PNG) Specification

    W3C PNG — pHYs Physical pixel dimensions: Defines the PNG chunk this converter uses to store DPI (unit specifier 1 = metre). w3.org/TR/png/#11pHYs

  • “Dots per inch (DPI) is a measure of spatial printing, video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch.”
    — Wikipedia — Dots per inch

    Wikipedia — Dots per inch: Background on DPI as a print density measure used in image briefs. en.wikipedia.org/wiki/Dots_per_inch

Frequently Asked Questions

Quick answers about this tool—open a question to read more.