PDF Compressor

Reduce your PDF file size by re-serializing the document. Note: embedded images are not re-encoded, so savings vary by document structure.

When should you use this?

Use this when a PDF's file size exceeds an email attachment limit, or gets blocked by a size cap when uploading to a web form.

When shouldn't you use this?

If the file already contains technical drawings or photos that need high resolution, aggressive compression can blur detail, always check the critical pages after compressing.

Step-by-step

Choose the document you want to shrink under PDF file. It is processed in your browser.
Click Compress and download.
The new file downloads automatically when it is ready. Compare its size with the original in your downloads folder.
Open the new file and check the page count, links and form fields before you use it.

Example

A job application portal caps uploads at a certain size, and the CV you exported from your word processor sits just over the limit. For a text-heavy file like that, re-serializing the structure is often enough to get under the cap. Try the same thing on a folder of receipts photographed with your phone and saved as one PDF, and the size may barely move. This tool doesn't re-encode embedded images, so the photos that make up most of that file stay as they are. To shrink a file like that, save the photos at a lower resolution and rebuild the PDF.

Why does a PDF get big and how does it shrink?

Most of a PDF's size comes from the images inside it, followed by embedded fonts, unused objects and metadata. Scanned documents carry every page as a picture, so they are the largest files. Compression is a trade-off between quality and size: the more an image is compressed, the smaller the file but the less sharp it is.

What to know before compressing

Know your limit first (for example 10 MB for email or a form) and do not compress more than needed.
Text-only PDFs are already small and may not shrink much.
Open the result and check small text and images.
Keep the original; compression cannot be undone.

Things to keep in mind

For image-heavy PDFs, resizing the images before building the PDF works far better than compressing afterwards.
An already optimized file may shrink very little. If the size barely changed, running it a second time won't help.
Changing the internal structure of a digitally signed PDF can invalidate the signature. Send signed documents as they are.
Keep the original until you have checked the compressed copy.

Frequently asked questions

Are my files uploaded to a server?

No. This tool runs entirely in your browser; your PDF file is never sent to a server.

Is there a file size limit?

There's no fixed limit, but very large files may process more slowly depending on your browser's available memory.

Does this work on password-protected PDFs?

No — password-protected PDFs can't be opened, so you'll need to remove the password first.