Skip to content

Compress PDF

Compress PDF files for free in your browser. Reduce file size by up to 70% without uploading. Choose compression level —

Compressing a PDF is the practical fix when an email bounces because of a size limit or when a CMS rejects an upload. OpenPDF recompresses images and optimises internal streams locally with pdf-lib, trimming image-heavy PDFs by 50-70% at the aggressive setting with no noticeable quality loss at balanced. Nothing is uploaded and the original file on disk is left untouched so you can re-export if needed.

How it works

  1. Load your PDF. Drop a PDF onto OpenPDF or click to browse. Large files are fine — there is no upload limit.
  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 — your file never leaves your device.
  4. Download the result. Compare the before/after sizes and download the smaller PDF.

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?

For image-heavy PDFs (scans, reports), aggressive compression typically cuts size by 50-70%. For text-only PDFs, the savings are smaller because PDFs already compress text well.

Will compression lose detail?

At balanced compression, the visible loss is typically invisible. Aggressive settings trade more detail for size — inspect scans or photos after compressing to make sure readability survives.

Is there a file-size limit?

No imposed cap. Browser memory is the only bound, and hundreds of MB are fine on most modern devices.

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 built around one principle: the PDFs you edit should never leave your device. Every tool — merge, split, sign, organize, annotate, compress, watermark, add page numbers — runs entirely in your browser using WebAssembly and modern JavaScript APIs. There is no upload step, no account, no email harvesting, and no premium tier gating the useful features. The codebase and the third-party scripts loaded for analytics and advertising are visible in the page source — Google AdSense and Google Analytics 4 load only after you accept cookies in the consent banner — so anyone can audit what is running before trusting the tool with sensitive contracts, scanned IDs, or financial documents.