Reduce PDF DPI

A PDF exported from design software or generated from a high-resolution scan can easily exceed 50MB because every embedded image is stored at 300 DPI or higher. That resolution is necessary for print, but it is completely unnecessary for screen viewing, web uploads, or email attachments. This tool reduces the DPI of embedded images inside your PDF to a target resolution you choose, bringing the file size down significantly while keeping all vector text and graphics crisp and unaffected.

How It Works

1. Upload your PDF: Drag the file onto the upload area or click to browse. The tool reads the document structure locally in your browser and displays the current page count and file size. A before-and-after size estimate appears once you configure your settings, so you can judge the reduction before committing.
2. Configure DPI and quality settings: Set your target DPI using the slider. Common reference points built into the tool are 300 DPI for print quality, 150 DPI for screen viewing, 96 DPI for web standard, and 72 DPI for email-friendly output. Choose an image quality level: High at 90%, Medium at 75%, Low at 60%, or Very Low at 40%. Select a compression method: JPEG works best for photos, ZIP works best for text-heavy graphics, and Auto Detect lets the tool decide per image type. Choose whether to apply changes to all pages, the current page, odd pages, or even pages. Enable the Preserve Text Quality toggle to keep vector text layers at full sharpness regardless of the image DPI target.
3. Process and download: Click Reduce PDF DPI. The tool resamples all embedded raster images to your chosen resolution directly in the browser. Download the reduced PDF once processing completes. Your original file remains unchanged on your device.

Compatibility and Support

Supported Input and Output Formats

• Input: PDF files containing embedded raster images, including high-resolution scanned documents, design exports from InDesign or Illustrator, image-heavy reports, and presentations exported as PDF with embedded photos
• Output: A DPI-reduced PDF with resampled image resolution at your chosen target DPI, with vector text and graphics preserved at full quality when the preserve toggle is enabled
• DPI range supported: 72 DPI (email optimized) through 300 DPI (print quality), with full control over the target via the slider

Unsupported Formats and Limitations

• Non-PDF formats: DOCX, XLSX, PPTX, JPG, and PNG files cannot be processed. Convert them to PDF first if DPI reduction is needed.
• Text-only PDFs: Documents containing only vector text and no embedded raster images will see little or no file size reduction since DPI reduction only affects raster image data.
• Password-protected PDFs: Encrypted files cannot be parsed for image processing. Remove the password protection before uploading.

File Size Limits

All processing runs locally in your browser with no server-imposed file size cap. PDFs with many high-resolution embedded images may take longer to resample on older devices. The before-and-after size estimate shown in the tool gives you a realistic preview of the output size before you start processing.

Who Should Use This Tool?

• Students: A student who scanned a 20-page research document at 600 DPI and needs to submit it through a university portal with a 10MB file size limit can reduce it to 150 DPI for screen-ready submission without rebuilding the scan.
• Freelancers and Designers: A graphic designer who delivered a 300 DPI print-ready catalog PDF to a client now needs a web-optimized version for the client's website. Running the same file through a 96 DPI reduction produces a web-ready version in seconds.
• Office Professionals: A sales manager sending a product brochure PDF by email repeatedly hits attachment size limits. Reducing embedded image DPI from 300 to 150 typically cuts the file size by 60 to 70 percent while keeping the document perfectly readable on screen.
• Developers: A developer building a document delivery pipeline can test different DPI and quality combinations here to find the right size-to-quality trade-off before encoding equivalent resampling logic in their server-side PDF processing workflow.

Why This Tool Beats the Alternatives

• Most free PDF compression tools apply a fixed quality reduction with no control over the target DPI. This tool lets you set a precise DPI value and see the estimated output size before processing.
• The option to choose between JPEG and ZIP compression per document type is absent from most free browser tools, which apply a single generic compression method regardless of content.
• The preserve vector text toggle prevents text sharpness from being affected during image resampling, a detail that basic compression tools ignore entirely.
• No account creation is required at any step. Competing platforms often require registration before allowing custom DPI or quality settings.
• Client-side processing means your document images, product photos, and visual content never pass through a third-party server, unlike all cloud-based PDF compression tools.

Pro Tips

• For email attachments, target 96 DPI with Medium quality and JPEG compression. This combination reliably reduces a print-ready PDF by 70 to 80 percent while keeping it fully readable on any screen.
• Always enable the Preserve Text Quality toggle when your PDF contains a mix of images and text. Without it, vector text layers may be rasterized at the lower target DPI, making body text appear slightly soft at normal zoom.
• If DPI reduction alone does not reach your target file size, follow up with the Compress PDF tool for a second pass. DPI reduction handles image resolution while general compression targets stream encoding, and both reductions stack.

Upload your PDF above to see the size estimate and start reducing image resolution to your chosen DPI target. For more granular control over individual embedded images, the Downsample Images in PDF tool offers per-image targeting alongside DPI reduction.