Image DPI Changer: 6 Free Tools Compared for 2026

A print shop rejects your file because it is 72 DPI. A journal submission portal flags your figures as "insufficient resolution." Your passport photo upload fails a 300 DPI requirement. The fix in every case is an image DPI changer — a tool that modifies the DPI metadata, resamples the pixel grid, or both.

But not all DPI changers work the same way. Some rewrite metadata without touching pixel data. Others resample the image to actually add or remove pixels. Some handle batch jobs, others are one-at-a-time. Picking the wrong tool wastes time or, worse, silently degrades your images.

This guide compares six free DPI changer tools — browser-based, CLI, and desktop — so you can pick the right one for the job. If you want a step-by-step walkthrough of the DPI-changing process itself, see our companion guide: How to Change DPI of an Image.

When Do You Need a DPI Changer?

DPI (dots per inch) controls how large an image prints at a given pixel count. A 3000 × 2400 px image at 300 DPI prints at 10 × 8 inches. The same image at 72 DPI prints at 41.7 × 33.3 inches — huge, but blurry up close. For a deeper dive into how resolution and pixel density relate, see What Is Image Resolution?.

Here are the most common scenarios where you need to change DPI:

If your target is web-only, DPI metadata does not matter — browsers render pixel dimensions, not DPI values. Focus on reducing image file size instead.

Tool Comparison

Here is how six free image DPI changer tools stack up. The key distinction: does the tool resample (add/remove pixels) or just rewrite metadata?

Top pick: Pixotter. No install. No account. Runs in your browser. Your images never leave your device. If you need a fast DPI change and do not want to install software or learn CLI syntax, start here.

Metadata-Only vs. Resampling — Know the Difference

Before diving into each tool, understand the two fundamentally different things a DPI changer can do:

Metadata-only change. The tool rewrites the DPI/PPI tag in the image file header. Pixel count stays identical. The image prints at a different physical size, but no quality is added or lost. A 2000 × 1500 px image tagged at 72 DPI becomes a 2000 × 1500 px image tagged at 300 DPI — it now prints at 6.67 × 5 inches instead of 27.8 × 20.8 inches. Use this when a print lab or submission portal requires a specific DPI value and your pixel count already supports the desired print size.

Resampling. The tool adds or removes pixels to hit a target resolution at a target DPI. Upsampling (adding pixels) uses interpolation algorithms like Lanczos or bicubic to fill in the gaps — useful but cannot invent detail that was never captured. Downsampling (removing pixels) reduces file size and dimensions. Use this when your image genuinely lacks enough pixels for the print size you need.

If you are unsure which approach your situation requires, check your image's current DPI first. Calculate whether your existing pixel count divided by the target DPI gives you the physical print size you need. If it does, a metadata-only change is sufficient. If the print would be too small, you need resampling.

1. Pixotter (Browser — Any OS)

Pixotter's resize tool handles DPI changes entirely in your browser via WebAssembly. No upload to any server, no account, no install. Drop your image, set target dimensions, download the result.

How to change DPI:

1. Open pixotter.com/resize.
2. Drop your image onto the page.
3. Enter the pixel dimensions that match your target DPI and print size. For 300 DPI at 8 × 10 inches: 2400 × 3000 px.
4. Click Resize and download.

Batch support: Yes. Drop multiple files and process them all at once. For large batches, see our batch resize images guide.

Strengths: Zero friction. Works on any OS with a modern browser. Privacy-first — your images stay on your device. Handles format conversion alongside DPI changes if you need to switch between JPEG and PNG.

Limitations: Resamples to target dimensions rather than editing DPI metadata directly. If you only need to rewrite the metadata tag without changing pixel count, use ExifTool or macOS Preview instead. You can also inspect existing metadata with Pixotter's metadata tool.

2. ImageMagick 7.1 (CLI — Cross-Platform)

ImageMagick is the Swiss Army knife of image processing. It handles both metadata-only DPI changes and full resampling from the command line. Licensed under Apache 2.0 — free for any use.

Install:

# macOS
brew install imagemagick

# Ubuntu / Debian
sudo apt install imagemagick

# Windows (winget)
winget install ImageMagick.ImageMagick

Metadata-only DPI change (no resampling — pixel count unchanged):

magick input.jpg -density 300 -units PixelsPerInch output.jpg

Resample to a new DPI at a specific print size (changes pixel count):

magick input.jpg -resample 300 output.jpg

This resamples the image so that it has 300 pixels per inch at its current physical dimensions. If the input is a 2000 × 1500 px image tagged at 72 DPI, the output will be approximately 8333 × 6250 px.

Batch processing:

for f in *.jpg; do magick "$f" -density 300 -units PixelsPerInch "output/$f"; done

Strengths: Handles virtually any image format. Scriptable for CI/CD pipelines and automated workflows. Both metadata-only and resample modes available.

Limitations: Requires CLI comfort. The -resample flag can produce very large files if the input has low DPI metadata — always check the math first.

3. ExifTool 12.76 (CLI — Cross-Platform)

ExifTool is a metadata editor, not an image processor. It rewrites the DPI tag in the file header without touching a single pixel. This is the cleanest option when a print service demands "300 DPI" and your image already has enough pixels — you just need the tag to say the right number. Licensed under the Artistic License / GPL.

Install:

# macOS
brew install exiftool

# Ubuntu / Debian
sudo apt install libimage-exiftool-perl

# Windows — download from exiftool.org

Change DPI metadata:

exiftool -XResolution=300 -YResolution=300 -ResolutionUnit=inches photo.jpg

Batch change all JPEGs in a folder:

exiftool -XResolution=300 -YResolution=300 -ResolutionUnit=inches *.jpg

ExifTool modifies files in place and creates .jpg_original backups by default. To skip backups, add -overwrite_original.

Strengths: Surgical precision — changes only what you ask it to. No risk of quality loss from unintended resampling. Handles JPEG, PNG, TIFF, and dozens of other formats. The fastest option for batch metadata-only DPI changes.

Limitations: Cannot resample. If your image needs more pixels, ExifTool cannot help — use ImageMagick, GIMP, or Pixotter to resize first, then set DPI metadata with ExifTool if needed.

4. IrfanView 4.67 (Windows)

IrfanView is a lightweight Windows image viewer with solid batch processing. Free for personal use (commercial use requires a $12 registration). It handles both resampling and metadata-only DPI changes through its GUI.

Change DPI for a single image:

1. Open your image in IrfanView 4.67.
2. Go to Image > Resize/Resample (or press Ctrl+R).
3. Set DPI in the resolution field.
4. To change metadata only: set the new DPI value and ensure Resample is unchecked.
5. To resample: check Resample, choose a filter (Lanczos is the sharpest), and enter target dimensions.
6. Click OK and save.

Batch DPI change:

1. Go to File > Batch Conversion/Rename.
2. Add your files.
3. Check Use advanced options and click Advanced.
4. Under Resize, set the DPI value and resample options.
5. Set the output directory and click Start Batch.

Strengths: Fast, lightweight (under 5 MB installed). Batch dialog processes hundreds of files. Supports dozens of formats with plugins.

Limitations: Windows only. The interface is functional but dated. Commercial use requires the paid registration.

5. macOS Preview (Built-In)

Preview ships with every Mac and can change DPI with or without resampling. No download, no cost.

Change DPI:

1. Open your image in Preview.
2. Go to Tools > Adjust Size.
3. The dialog shows current width, height, and resolution (PPI).
4. To change metadata only: uncheck Resample image, then set the Resolution field to your target (e.g., 300 pixels/inch). Pixel dimensions stay fixed; physical print size recalculates.
5. To resample: check Resample image, then set both Resolution and physical dimensions. Preview resamples the pixel grid to match.
6. Save the file.

Batch support: Not built in. You can open multiple images and use Tools > Adjust Size on the selection, but it is clunky for large batches. For serious batch work on macOS, use ImageMagick or Pixotter.

Strengths: Already installed. Handles both metadata-only and resample workflows. Writes correct PPI metadata that print labs recognize.

Limitations: macOS only. No CLI access for scripting. Limited resampling algorithm choices compared to ImageMagick or GIMP.

6. GIMP 2.10 (Cross-Platform)

GIMP is a full image editor that includes DPI controls within its canvas and export workflows. Licensed under GPL-3.0 — free and open source.

Change DPI:

1. Open your image in GIMP 2.10.
2. Go to Image > Print Size.
3. Set the X resolution and Y resolution to your target DPI (e.g., 300 pixels/in). This changes metadata only — pixel count stays the same, physical print size adjusts.
4. Click OK.

Resample to a new size at a target DPI:

1. Go to Image > Scale Image.
2. Set the desired width and height in pixels (or set physical size and DPI together).
3. Choose an interpolation method — NoHalo or LoHalo for best quality.
4. Click Scale.
5. Export via File > Export As.

Batch support: Not native. The Script-Fu console or GIMP's Python-Fu can batch-process files, but the setup is significantly more involved than ImageMagick's one-liner. For batch DPI changes, ImageMagick or ExifTool are faster choices.

Strengths: Full editing suite — you can retouch, crop, and adjust DPI in one session. Cross-platform. Excellent interpolation algorithms for upscaling.

Limitations: Heavy install (~300 MB). Overkill if you only need a DPI change. Startup time is slow compared to lighter tools.

Which Image DPI Changer Should You Use?

Skip the comparison table and go straight to the answer for your situation:

• "I need to change DPI right now, no install." Use Pixotter. Open the browser, drop the image, done.
• "I just need the DPI tag to say 300 — my pixels are fine." Use ExifTool 12.76. One command, metadata only, zero quality risk.
• "I need to resample and I want CLI control." Use ImageMagick 7.1. Scriptable, precise, handles any format.
• "I'm on Windows and want a GUI." Use IrfanView 4.67. Lightweight, fast, solid batch dialog.
• "I'm on a Mac and don't want to install anything." Use macOS Preview. Already there, works for single images.
• "I need to edit the image AND change DPI." Use GIMP 2.10. Full editor with DPI controls built in.

For most people, the fastest path is Pixotter for one-off jobs and ImageMagick for batch scripting. ExifTool fills the niche case where you need metadata-only changes at scale.

FAQ

What does an image DPI changer actually change?

It depends on the tool and mode. A metadata-only DPI changer rewrites the resolution tag stored in the image file header (XResolution / YResolution in EXIF data). The pixel grid stays identical — no data is added or removed. A resampling DPI changer adds or removes pixels to achieve a target resolution at a target physical size. Both are valid approaches; the right choice depends on whether your current pixel count already supports your target print size.

Can I change DPI without losing quality?

Yes — if you use a metadata-only change. Tools like ExifTool, macOS Preview (with "Resample image" unchecked), and ImageMagick's -density flag rewrite the DPI tag without modifying pixels. Quality is preserved because the image data is untouched. Resampling introduces interpolation, which can reduce sharpness when upscaling — though modern algorithms (Lanczos, Preserve Details 2.0) minimize the loss.

Is 72 DPI vs 300 DPI the same for web images?

On screen, yes. Browsers ignore DPI metadata entirely and render images based on pixel dimensions. A 1200 × 800 px image at 72 DPI and the same image at 300 DPI look identical in a browser. The 72 DPI convention is a holdover from early Macintosh displays and has no technical significance for web use. If your images are web-only, focus on pixel dimensions and file size optimization instead.

How do I change DPI for multiple images at once?

For batch DPI changes, your best options are: Pixotter (drag and drop multiple files in the browser), ImageMagick (shell loop over files), ExifTool (wildcard syntax on a directory — metadata-only), or IrfanView's batch dialog (Windows GUI). See our full batch resize guide for detailed instructions on each method.

Does changing DPI affect file size?

A metadata-only DPI change has virtually no effect on file size — you are modifying a few bytes in the file header. Resampling changes file size proportionally to the pixel count change. Upsampling from 72 DPI to 300 DPI with resampling can increase file size dramatically. If file size is a concern after resampling, run the image through a compressor — Pixotter's compress tool or ImageMagick's quality flag both work.

What DPI should I use for printing photos?

300 DPI is the standard for prints viewed at arm's length (photo prints, magazines, book pages). For large-format prints viewed from several feet away (posters, banners), 150 DPI is sufficient and produces much smaller files. Newspapers typically use 150–200 DPI. Going above 300 DPI for standard photo prints provides no visible improvement — the human eye cannot distinguish the difference at normal viewing distance.

Why does a print lab reject my 72 DPI image even though it looks fine?

Many print labs check the DPI metadata tag automatically during upload validation. Even if your image has enough pixels for a sharp print, a 72 DPI tag can trigger an automatic rejection. The fix is a metadata-only DPI change — set the tag to 300 using ExifTool, macOS Preview, or ImageMagick's -density flag. Your pixels stay the same; the tag satisfies the validator.

What is the difference between DPI and PPI?

DPI (dots per inch) technically refers to how many ink dots a printer deposits per inch of paper. PPI (pixels per inch) refers to how many pixels are packed into one inch of a digital image at its native size. When people say "change DPI," they almost always mean changing the PPI metadata in the image file. The terms are used interchangeably in practice, and every tool in this guide works with the PPI value stored in the image header — which printers and software interpret as DPI for print sizing.