PDF Compressor

Compress PDF Files Free: Up to 80% Smaller

Large PDF files cause real problems: email attachments bounce, uploads time out, shared drives fill up, and loading times slow to a crawl. Our free online PDF compressor solves all of that: reducing file size dramatically without requiring any software installation, account registration, or subscription payment. Two compression methods are available. Choose the one that fits your needs: a fast, lossless browser-based compression for privacy-sensitive files, or a deeper server-side compression for the maximum possible size reduction.

Two Compression Methods

Browser Compression: Lossless & 100% Private

Browser compression processes your PDF entirely within your web browser using pdf-lib. It achieves size reduction by:

• Stripping embedded metadata (title, author, subject, keywords, producer, creator)
• Re-writing the PDF using object stream compression (PDF 1.5 format)
• Removing redundant cross-reference data

This method is completely lossless: every character of text remains fully selectable and searchable, every image stays at its original resolution, and every font is preserved exactly as in the original. Your file is never sent to any server. We log nothing. Browser compression works best on PDFs that contain a lot of uncompressed text, metadata, or structural overhead. Heavily image-based PDFs may see little reduction with this method: use server compression for those.

Server Compression: Up to 80% Smaller

For the maximum reduction: especially on PDFs packed with high-resolution images: server compression uses Ghostscript, the industry-standard PDF and PostScript interpreter. Ghostscript resamples embedded images to a lower DPI, re-encodes them at reduced quality, and rebuilds the PDF efficiently. Three levels are available:

• Low (200 DPI): gentle compression, 20–35% reduction, images remain sharp
• Recommended (150 DPI): balanced quality and size, 40–60% reduction, ideal for most PDFs
• Extreme (72–96 DPI): maximum compression, 60–80% reduction, noticeable image quality reduction

Text in server-compressed PDFs remains selectable and searchable: only images are resampled. This method sends your file to the server for processing. The file is deleted immediately after compression is complete. No logs are kept.

Which Method Should I Use?

• Text-heavy PDFs (reports, contracts, slides with little imagery): start with Browser compression. It is lossless and private. If the result is not small enough, try server compression at the Low level.
• Image-heavy PDFs (brochures, portfolios, scanned documents, magazines): use Server compression at the Recommended level for the best balance of quality and size.
• Sensitive documents (legal, financial, medical): use Browser compression. Your file never leaves your device.
• Emailing large attachments: Server compression at Extreme can get most PDFs under the common 10 MB or 25 MB email attachment limits.

Who Uses a PDF Compressor?

• Office workers: shrink reports, presentations, and invoices before emailing
• Students: reduce thesis and assignment file sizes to meet upload limits on submission portals
• Designers & photographers: compress image-heavy portfolios for web delivery
• Real estate agents: shrink property brochures for fast loading on listing sites
• Legal professionals: reduce case file sizes for court submission portals with strict limits
• Web developers: optimise PDF downloads embedded in websites

How to Compress a PDF Online

1. Upload your PDF: drag and drop or click to browse. The file is loaded into the tool instantly.
2. Choose a compression method: Browser (lossless, private) or Server (deeper compression).
3. Select a compression level (server only): Low, Recommended, or Extreme.
4. Click Compress: the result shows original vs. compressed file size and the reduction percentage.
5. Download: click Download Compressed PDF to save the result.

Free, Private & No Limits

This PDF compressor is completely free to use with no sign-up and no usage limits. There is no maximum number of files you can compress, and no subscription is needed to access any compression level. Your files are handled with complete respect for your privacy: browser mode never leaves your device, and server mode deletes your file immediately after compression.