Compress PDF Online Free: Reduce PDF Size
Compress PDF files in your browser. Lossless metadata strip or image mode with quality slider.
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How to Compress PDF Files Online
Drop your PDF file into the upload zone above. Choose lossless mode to strip metadata while keeping text selectable, or image mode to convert pages to JPEG for maximum size reduction. Click Compress PDF and download the result.
Lossless vs Image Mode
Lossless mode uses pdf-lib to re-save the PDF and strip all metadata fields. The file size reduction is modest but text remains selectable. Image mode uses pdf.js to render each page to a JPEG canvas, then rebuilds the PDF from those images. This produces much smaller files but converts text to pixels.
Privacy and Security
All compression happens in your browser. Your PDF file is never uploaded to any server. The tool uses pdf-lib and pdf.js libraries loaded from CDN, and all processing runs locally in your device RAM.
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Frequently Asked Questions
How does PDF compression work?
Lossless mode strips metadata and re-saves with pdf-lib. Image mode renders each page to JPEG and rebuilds the PDF, which reduces size significantly but removes selectable text. The tool shows before/after sizes.
What is the difference between lossless and image mode?
Lossless keeps all text and vector data intact while stripping metadata. Image mode converts every page to a JPEG image, which compresses much more but makes text unselectable and searchable.
Do you upload my PDF?
No. All compression happens in your browser using pdf-lib and pdf.js. Your file never leaves your device.
Is there a file size limit?
No. The tool has no file size cap. Compression runs entirely in your browser RAM. Very large files may take longer depending on your device.
Can I control the image quality?
Yes. Image mode has a quality slider from 10 to 100. Lower quality produces smaller files. 70 is a good balance for most documents.
Will compression affect page layout?
Lossless mode preserves layout exactly. Image mode preserves visual layout but converts text to pixels, so text is no longer selectable.