PDF Compressor

Shrink a PDF's file size by removing redundant internal structure.

  • Typical savings: a few percent to ~15%

Honest heads-up: this optimizes the PDF's internal structure but doesn't recompress embedded images — for PDFs made mostly of large scanned images, savings will be modest. Our Pro compressor recompresses embedded images too and typically does much better on those.

Select a PDF to compress

or drop it here.

What this free compressor does

A PDF is a container: text, fonts, vector graphics and images, plus a lot of internal bookkeeping. This free tool rewrites the file more efficiently by removing redundant internal structure. That typically saves a few percent up to about 15%, and it never changes how the document looks.

It does not recompress the images inside the PDF. For many PDFs that is fine, because their size comes from structure. But for PDFs that are mostly big images — scanned documents, photo books, brochures — most of the size is the images, so the savings from structure alone will be modest. Pro recompresses the embedded images too, which typically gives 3–5 times more reduction on those files.

Why is my PDF so large?

  • Scans are pictures. A 20-page scan at 600 dpi can easily be 50 MB or more, even though it holds very little actual data.
  • Phone photos are huge. A PDF built from full-resolution camera photos carries every pixel.
  • Embedded fonts and old edits can add weight, which is what the free compressor trims.

How to get a much smaller PDF for free

  1. Shrink the pictures before building the PDF. Run your photos or scans through the Image Compressor, then combine them with Image to PDF. This is usually the biggest saving available.
  2. Scan at a lower resolution. 150–200 dpi is comfortable to read on screen and for email; 300 dpi is plenty for text that you also want OCR to read. 600 dpi is rarely worth the size.
  3. Remove pages you don't need with Rearrange PDF or Split PDF.

Is it private?

The free compressor works in your browser; your PDF isn't uploaded. (Pro's batch image recompression runs on our server, and files are deleted as soon as the job finishes.)

Frequently asked questions

Why did my PDF barely get smaller?

Almost certainly because it's mostly images. Use the tips above to shrink the images, or try Pro, which recompresses them.

Will compressing change how my PDF looks?

The free compressor doesn't touch the visible content, so the document looks identical. Image recompression (Pro) trades a small amount of image detail for a much smaller file, and you choose the quality level.

What size limit do email providers have?

It varies by provider; many allow attachments of roughly 20–25 MB. Check your provider's current limit, and consider sharing a link to a cloud-stored file for anything bigger.

Related tools