Compress PDF
Reduce PDF file size online with lossless and lossy compression. 100% browser-based, no upload required.
How do I compress a PDF file online?
Upload your PDF file to this tool, choose between lossless or lossy compression mode, optionally enable metadata removal and fast web view optimization, then click compress. The entire process runs in your browser — no files are uploaded to any server.
What is the difference between lossless and lossy PDF compression?
Lossless compression re-serializes the PDF structure using pdf-lib, removing metadata and compressing streams without altering content. It preserves text selectability and exact visual fidelity, typically reducing size by 10-30%. Lossy compression renders each page as a JPEG image using pdf.js and rebuilds the PDF, achieving 50-80%+ reduction but text becomes non-selectable and non-searchable.
Is my PDF data safe with this tool?
Yes, absolutely. All PDF compression is performed locally in your browser using JavaScript. No files are uploaded to any server. Your documents remain completely private and are never transmitted over the internet.
How much can I reduce my PDF file size?
It depends on the compression mode and file content. Lossless mode typically achieves 10-30% reduction, with greater savings on files containing redundant metadata or uncompressed streams. Lossy mode can reduce file size by 50-80% or more, especially for PDFs with embedded images or complex vector graphics.
Does PDF compression reduce quality?
In lossless mode, quality is perfectly preserved — the output is visually identical to the original. In lossy mode, each page is converted to a JPEG image at 2x scale and 80% quality, which introduces slight compression artifacts but maintains good readability. The trade-off is that text becomes non-selectable in lossy mode.
What does removing PDF metadata do?
It strips hidden document properties including author name, title, subject, keywords, creator application, and producer information. This data is not visible in page content but adds to file size and may contain sensitive information such as editing history or organizational details.
What is fast web view optimization?
Fast web view (linearization) reorganizes the PDF internal structure so the first page can display before the entire file finishes downloading. This significantly improves loading speed when viewing PDFs in a web browser, especially for large documents shared via links.
Can I compress multiple PDF files at once?
Yes, you can upload multiple PDF files simultaneously. After compression, all files are packaged into a single ZIP archive for convenient download. A re-download button is also available if you need to download the ZIP again without re-processing.
Does this PDF compressor work on mobile phones?
Yes, this tool works on any modern browser including Chrome, Safari, Firefox, and Edge on both desktop and mobile devices. Since all processing happens in your browser, it works equally well on Android phones, iPhones, tablets, and computers.
What is the maximum PDF file size I can compress?
Since compression runs entirely in your browser, the limit depends on your device memory. Typically, files up to 200-500 MB can be processed on modern devices with sufficient RAM. For very large files, we recommend using a desktop browser with adequate memory.
Will the compressed PDF look the same?
In lossless mode, the output is pixel-for-pixel identical to the original — no visual difference whatsoever. In lossy mode, the visual appearance is very close but may show slight JPEG compression artifacts, particularly around sharp text edges or fine details.
Why is my PDF already small after lossless compression?
If your PDF was already created with optimized settings (compressed streams, no redundant metadata), lossless compression may achieve minimal reduction. For maximum size reduction, use lossy mode which converts pages to compressed JPEG images.
How to Use Compress PDF
Compress PDF reduces the size of your PDF files right in your browser, with lossless or lossy modes — no upload required. Your documents never leave your device.
- Select or drop the PDF file you want to shrink.
- Choose 'Lossless (light compression)' to preserve every detail, or 'Lossy (high compression)' for the smallest possible file.
- Tick 'Remove metadata' to strip document properties such as author and creation details.
- Tick 'Optimize for fast web viewing' so the PDF can display page-by-page when opened online.
- Run the compression and download the smaller PDF from your browser.
Try 'Lossless (light compression)' first for scans you need to archive; if the file is still too big, run it again with 'Lossy (high compression)' and compare quality.
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