Let Compress

Compress PDF

Compress PDF online free in your browser. Reduce PDF file size without uploading your documents.

or drop files here

Maximum file size: 100MB per file

High Quality

Maintain file quality while reducing file size up to 80%.

100% Secure

All processing happens in your browser. Your files never leave your device.

Super Fast

Compress multiple files in seconds with our optimised algorithms.

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About PDF Compression Technology

Where the bytes hide inside a PDF

Unlike a JPEG or PNG, a PDF is a container of objects — and almost none of its size comes from the visible text. The bulk is usually raster images embedded at full resolution (scanned pages, screenshots, inserted photos), complete font files bundled with every glyph even when only a handful are used, and content streams stored uncompressed or under generic Flate (zlib) encoding. Audit any "bloated" PDF and you will typically find one or two of these levers barely touched.

The three levers: image downsampling, font subsetting, stream recompression

Effective PDF compression pulls all three levers together. Embedded raster images are downsampled to the display resolution and re-encoded (a 600 DPI scan destined for screen rarely needs more than 150 DPI). Fonts are subsetted so only the glyphs actually referenced on the page travel with the file. Object streams and page content are recompressed, duplicate objects merged, and redundant metadata, embedded thumbnails, and unused resources stripped. Crucially, the vector text itself stays vector — sharp at any zoom — because we compress the assets around the text, not the text.

Private by construction — parsing happens in your browser

Every PDF is parsed, restructured, and rewritten locally through the browser's WebAssembly and PDF.js pipeline, so nothing is transmitted to a server. There is no upload step, no transient copy on a remote disk, and no queue. That matters most for the documents people actually compress — contracts, tax forms, medical and legal files — where "your file is deleted after processing" is a weaker guarantee than "your file was never uploaded."

Made for Users in Australia

Australian internet ranges from fast NBN fibre in the capitals to satellite and fixed-wireless in regional and remote areas. Keeping files small is essential for reliable sharing across the NBN, for uploads to myGov and state services, and for delivering content to audiences on Telstra, Optus, and Vodafone mobile networks across vast distances.

  • myGov and state government portals enforce upload limits — compress scanned IDs and documents before lodging them.
  • For regional users on fixed-wireless or satellite NBN, smaller files mean fewer timeouts on slower, higher-latency links.
  • Australian mobile plans often include data caps; pre-compressed media saves data for end users on the go.
  • When sharing with New Zealand and Southeast Asia, smaller attachments transfer more reliably across trans-Tasman links.
How to Compress a PDF Online
  1. 1
    Upload your PDF files

    Select one or more PDF documents from your device using the upload button or drag-and-drop area.

  2. 2
    Choose a compression level

    Pick the quality setting that best matches your goal, such as balanced compression for email or stronger reduction for web delivery.

  3. 3
    Compress and download

    Process the PDFs directly in your browser and download the smaller files individually or together as a ZIP archive.

Frequently Asked Questions

How do I compress a PDF file?

Simply drag and drop your PDF file into the upload area above, select your preferred compression level, and click "Compress All PDFs". Your compressed PDF will be ready for download in seconds. The entire process happens in your browser - no file upload to any server.

Is this PDF compressor free?

Yes, our PDF compressor is 100% free with no hidden costs, no registration required, and no watermarks added to your documents. You can compress unlimited PDF files without any restrictions.

Is my PDF data secure and private?

Absolutely. All PDF compression happens directly in your browser using client-side JavaScript. Your files never leave your device or get uploaded to any server. This ensures maximum privacy and security for sensitive documents.

How much can I reduce PDF file size?

PDF compression typically reduces file size by 50-90% depending on the original content. PDFs with high-resolution images can see the most dramatic reduction, while text-heavy PDFs may see more modest gains.

Will compression affect PDF quality?

Our compression algorithm intelligently optimizes images and removes redundant data while preserving text clarity and document structure. The "Recommended" setting provides the best balance between file size and quality for most use cases.

Can I compress multiple PDF files at once?

Yes! You can select multiple PDF files and compress them all at once. The compressed files can be downloaded individually or as a ZIP archive for convenience.

How to compress a PDF file for email?

Upload your PDF, choose your compression level, and download the smaller file. Our tool handles everything in your browser — no server upload needed.

Can I compress an already compressed PDF?

Yes! Our advanced PDF compressor can further reduce already-compressed PDFs by optimizing images, fonts, and removing redundant data while preserving readability.

How to reduce PDF size without losing quality?

Our PDF compressor uses smart optimization to reduce file size while preserving text sharpness and image clarity. Upload, compress, and download — all in your browser.

Can I compress files for myGov and state government portals?

Yes. myGov and state services often limit document sizes. Our tools help you get scans and forms under those limits before you upload them.

Will this work on slow regional or satellite NBN?

Yes. Because files are processed locally and never uploaded, the tool works well even on fixed-wireless and satellite connections where upload speeds are limited.

Does it respect my data cap?

Absolutely. Since nothing is uploaded, you only use data for the final, smaller download — ideal for Australians on metered mobile and NBN plans.

What file formats are supported?

We support PNG, JPG, WebP, AVIF, GIF, BMP, PDF, and many more. Check each tool page for its specific format support.

Why Choose Let Compress?
  • No upload — saves your NBN and mobile data allowance
  • 100% free, no sign-up — no subscriptions or hidden fees
  • Reliable on slower regional, fixed-wireless, and satellite NBN connections
  • Batch processing for busy Australian workflows
  • Works in any modern browser — nothing to install
  • Privacy by design — your files stay on your device

Learn More About File Compression

Explore these authoritative resources to deepen your understanding of file compression and optimisation.

MDN Web Docs: Image Optimisation

Comprehensive guide on image optimisation for web performance by Mozilla.

Google Web Fundamentals: Image Optimisation

Best practices for image optimisation from Google's web performance team.

W3C WebP Specification

Official W3C specification for the WebP image format.