How to compress a PDF so it fits in an email

Most email services stop attachments at about 20–25 MB, and many company mail servers cap them at 10 MB. Scanned documents and PDFs full of photos easily go over that. Here is how to make the file small enough to send, without uploading it to a website.

Step by step

1. Open the Compress PDF tool.
2. Click the upload area or drag your PDF onto it. The file is opened by your browser — it is not sent to a server.
3. Choose a compression level:
   • Recommended — the right choice for most emails; a good balance of size and sharpness.
   • High compression — the smallest file, for strict limits such as 2–5 MB upload forms.
   • Low compression — keeps the best image quality when you only need a small reduction.
4. Click Compress PDF, check the new size shown in the result, and click Download PDF.

Why some PDFs shrink a lot and others barely change

Compression works by re-rendering each page as an optimized image. That is very effective for scans, photos and image-heavy brochures, which often drop by 70–90%. A PDF that is mostly plain text is already small, so it has little to lose.

If you need the text to stay selectable and copyable, turn on Keep text selectable. The file will keep its text layer, but the size reduction will be much smaller.

Tips if the file is still too big

• Try High compression before anything else.
• Remove pages you don’t need with Delete Pages, then compress again.
• Split a very long document into parts with Split PDF and send them in separate emails.
• Scanning a paper document? Scan at 150–200 DPI in grayscale instead of 600 DPI colour — the PDF will start out far smaller.

Is it safe for confidential documents?

Yes. PDFmoor runs the compression inside your own browser, so contracts, payslips or medical letters never leave your device. You can even disconnect from the internet after the page has loaded and the tool still works.