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Compress PDF

Compress PDF files for free in your browser. Choose a level and review the resulting size and document properties; savings depend on the source PDF.

  • Try to reduce file size locally in your browser
  • Choose compression level: low, medium, high
  • Review size, readability and document properties after exporting

Compressing a PDF can help when an email or CMS has a size limit. OpenPDF tries to recompress images and optimise streams locally; the result depends on the source PDF and selected level. Medium and high settings can rasterize pages, remove selectable text or invalidate signatures, so inspect the output. The original file remains available for another export.

How it works

  1. Load your PDF. Drop a PDF onto OpenPDF or click to browse. Limits depend on the document, compression level and browser/device resources.
  2. Pick a compression level. Choose aggressive, balanced, or light compression based on how much quality you can trade for size.
  3. Compress in the browser. OpenPDF recompresses images and optimises streams locally with pdf-lib; inspect the result and its preserved properties.
  4. Download the result. Compare the before/after sizes, check the result and download the copy you want to keep. Compression may leave the size unchanged.

Common use cases

  • Shrinking a scanned PDF so it fits under an email attachment size limit.
  • Compressing a heavy image-rich report before uploading to a slow CMS.
  • Reducing the size of bank statements and receipts for a cloud archive that charges per GB.
  • Squeezing a multi-page scan down so it can be submitted through a form with a 5 MB cap.

Frequently asked questions

How much can OpenPDF compress a PDF?

The result depends on the source PDF and selected level. Some PDFs become smaller, while others show little improvement or keep the original when an attempted result is larger; inspect the output before sharing.

Will compression lose detail?

Medium and high compression can rasterize pages, remove selectable text and invalidate existing signatures. Review readability and required PDF properties after compression, especially for scans or signed documents.

What limits apply to compression?

Compression accepts files up to 150 MiB. The page limit depends on the document: the engine allows up to 600 pages for text-dominant PDFs and up to 200 pages for raster-dominant PDFs. Browser/device resources can impose a lower practical limit.

Is my file uploaded to compress it?

No. pdf-lib recompresses images and optimises streams locally in your browser. Nothing is uploaded.

Why OpenPDF

OpenPDF is an independent project where PDF document processing runs in the browser using WebAssembly and modern JavaScript APIs. The toolkit includes merge, split, sign, organize, annotate, compress, watermark, page numbers, add image and fill forms. Practical limits depend on the operation, document and device. The page source and privacy policy describe consent controls, analytics, advertising and optional services before you use the tool with sensitive documents.

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