Compress PDF — Reduce File Size Online Free
Reduce your PDF file size while maintaining quality. Instantly. No sign-up required.
How to compress pdf
- 1Upload your PDF file using the drop zone above
- 2Select your compression level (low, medium, or high)
- 3Click "Compress PDF" to reduce the file size
- 4Download your compressed PDF
About This Tool
Large PDF files can be a headache — they clog up email attachments, slow down cloud uploads, and eat through storage quotas. Our free online tool lets you compress PDF documents in seconds, shrinking file size while preserving the content you care about.
The compressor works by rebuilding the internal structure of your PDF, removing orphaned objects, stripping unnecessary metadata, and optimizing the cross-reference table. You choose the compression level: low keeps everything intact for minimal size reduction, medium strips document metadata like title and author for a balanced result, and high aggressively removes all non-essential data for the maximum possible reduction.
Because the entire process runs inside your browser, your files are never uploaded to a server. This means you can compress PDF files that contain sensitive or confidential information without worrying about privacy. There are no file-size limits, no watermarks, and no daily caps — just fast, free compression whenever you need it.
Whether you need to compress a single report or batch-process documents before archiving, this tool has you covered. Pair it with our other PDF utilities — merge, split, convert — to build a complete document workflow without leaving your browser.
Frequently Asked Questions
Our compressor reduces file size by removing unused objects and metadata — it does not resample images or alter visible content. At the low and medium levels, the pages look identical to the original. The high level strips all metadata but still preserves page content.
There is no hard limit. Because the tool runs entirely in your browser, performance depends on your device's available memory. Most files up to 100 MB compress without any issues.
No. All processing happens locally in your browser using JavaScript. Your PDF never leaves your device, making this tool safe for confidential or sensitive documents.
Results vary depending on the original file. PDFs with lots of unused objects, embedded metadata, or bloated cross-reference tables see the biggest reductions — sometimes 20-50%. Already-optimized files may see a smaller improvement.
The tool attempts to process protected files by ignoring encryption flags. It works in most cases, but heavily encrypted documents may not compress successfully. Try our Unlock PDF tool first if you run into issues.