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PDF Tools

PDF Compress

Compress PDF files by removing unnecessary metadata, optimizing images, and reducing stream data. Choose compression levels from low to maximum. Processed locally with no uploads.

PDF tools

In brief

Compress PDF files by removing unnecessary metadata, optimizing images, and reducing stream data. Choose compression levels from low to maximum. Processed locally with no uploads.

Reviewed: 2026-09-18

What this tool supports

  • Compress PDF files by removing unnecessary metadata, optimizing images, and reducing stream data. Choose compression levels from low to maximum. Processed locally with no uploads.
  • All processing runs locally in your browser
  • No data uploaded, stored, or transmitted
  • Works offline after initial page load
  • Instant results with download support

How to use PDF Compress

Reduce PDF file size entirely in your browser. Choose compression level for the best balance of size and quality. No uploads required.

  • Step 1

    Upload your PDF

    Drag and drop or click to upload. The tool accepts standard PDF files of any size.

  • Step 2

    Choose compression level

    Select Low, Medium, or High compression. The tool shows an estimated size reduction for each level.

  • Step 3

    Compress the PDF

    Click Compress to process the file. The browser optimizes the PDF structure locally.

  • Step 4

    Download the compressed PDF

    Save the smaller PDF to your device. Compare the file sizes to see the reduction.

Common mistakes

Compressing already-compressed PDFs expecting significant reduction

Consequence: Double compression provides minimal size reduction but may degrade embedded image quality.

Fix: Check the original file size first. Heavily compressed PDFs won't benefit much from re-compression.

Using maximum compression for print-quality documents

Consequence: High compression can make text fuzzy and images pixelated in printed output.

Fix: Use low or medium compression for documents intended for printing.

Expecting compression to fix corrupted PDFs

Consequence: Compression works on valid PDF structures; corrupted files may fail or produce worse output.

Fix: Validate the PDF first. Use a repair tool for corrupted files before compressing.

Expecting text-only PDFs to compress significantly

Consequence: PDFs with mostly text have little redundant data to compress.

Fix: Text-heavy PDFs may only compress 5-15%. Image-heavy PDFs compress much more.

Compressing already-optimized PDFs

Consequence: Re-compressing a PDF that is already optimized may not reduce size further.

Fix: Check the original file size before compressing to set realistic expectations.

Best practices

  • Choose the quality level before comparing outputs — lower quality reduces size more but is irreversible once the original is discarded.
  • Test one representative page range first when compressing very large documents, then apply the chosen level to the full file.
  • Expect image-heavy documents to compress more than text-only ones; text pages compress little because fonts are already compact.
  • Keep the original file until the compressed output is verified at the intended display or print size.

Connected workflows

Reduce a scan archive

PDF Compress

Shrink large scanned PDFs for long-term storage or email attachment limits while keeping text legible.

  1. Upload the scanned PDF
  2. Select a quality level
  3. Compress and compare the size reduction
  4. Download the compressed document

Prepare a document for upload limits

PDF Compress

Compress a PDF to fit a portal’s maximum file-size requirement, checking readability of the smallest pages afterwards.

  1. Upload the source PDF
  2. Choose the quality level matching the size limit
  3. Compress and verify readability
  4. Download the result

Browser limitations

  • Very large files may be slow to process
  • Browser memory limits apply to very large images; files of several hundred megabytes are processed in a Web Worker with graceful degradation

Authoritative resources

PDF SpecificationPublisher: Adobe · Reviewed: 2026-09-18

Concrete examples

Input
Sample input
Result
Result

Example usage.

Frequently asked questions

How does PDF compression work?

The tool analyzes your PDF structure, removes redundant metadata, optimizes embedded images, and recompresses streams. Processing happens entirely in your browser.

How much can compression reduce file size?

Reduction varies by content. PDFs with large images typically see 30-70% reduction. Text-heavy PDFs compress less (10-20%). The tool shows the before/after sizes.

Does compression reduce visual quality?

The tool offers compression levels: Low (minimal change), Medium (balanced), and High (smallest size). Higher compression may reduce image quality slightly.

Is my PDF uploaded to a server?

No. All compression happens locally in your browser. Your PDF data never leaves your device.

Can I compress encrypted PDFs?

The tool can process most standard PDFs. Password-protected PDFs may need to be unlocked first before compression.

How much can PDF compression reduce file size?

Compression typically reduces file size by 30-70%, depending on the original content.

Does compression affect PDF quality?

Basic compression preserves quality. Strong compression may reduce image resolution slightly.

Can I compress password-protected PDFs?

You need to enter the correct password before compression.

Privacy and offline behavior

PDF Compress re-encodes the uploaded document inside this browser tab and writes the compressed file locally. Page content and metadata never leave the device; files are used only on explicit user action, and the page continues to work offline after the initial load.