To compress a PDF for email, shrink the pictures inside it: that’s where almost all the size is. Open it in the JFDI PDF toolkit, go to the Finish tab, choose Balanced (or Smallest for a tight limit) under Making the file smaller, and download. The new size is shown next to the old one. It’s free, there’s no upload, and there’s no file-size cap.
How big can an email attachment be?
| Email service | Limit | Source |
|---|---|---|
| Gmail (personal) | 25 MB; anything bigger is sent as a Google Drive link | |
| Outlook with an internet account such as Outlook.com | 20 MB | Microsoft |
| Outlook with a work (Exchange) account | 10 MB by default; your IT team may have changed it | Microsoft |
Outlook’s limit covers the whole email, and the way attachments are encoded for sending can add up to a third to their size on some systems, so aim well under the limit. For a 10 MB limit, aim for 7 MB.
Step by step
- Open the PDF toolkit and drop in your PDF, or choose Compress on the start page.
- Go to the Finish tab and find Making the file smaller.
- Choose a setting (see the table below). Start with Balanced.
- Download PDF. The message shows the new size beside the old one. If it’s still too big, try Small or Smallest.
| Setting | Pictures become | Good for |
|---|---|---|
| Keep as they are | Unchanged | Text documents, or when quality matters most |
| Balanced | Up to 2,200 pixels, good-quality JPEG | Most files: noticeably smaller, no visible loss on screen |
| Small | Up to 1,500 pixels | Sharing and reading on screen |
| Smallest | Up to 1,000 pixels, lower quality | Email with a strict size limit |
Pictures are only replaced when the result is actually smaller. Unused data, including pages you deleted, is always removed.
Why some PDFs barely shrink
Compression works on pictures. A PDF that’s mostly text, such as a report exported from Word, is already compact: a page of text takes a few kilobytes, so there’s little to remove. If such a file is large, it’s usually because of:
- Embedded fonts, especially several large ones. These can’t be removed without changing how the text looks.
- Vector drawings such as detailed maps, plans or charts with thousands of points. For these, Turn every page into a picture (150 dpi) can help, but the text then can’t be selected, searched or read by screen readers.
- Lots of pages. Split the document instead: the Finish tab can split a PDF into several files by page ranges.
Scanned documents are the opposite: every page is a full-size photo, so they often shrink by most of their size.
Other ways to get under the limit
- Remove pages nobody needs, such as blank pages from a scanner, in the Pages tab.
- Split the file into two emails with Splitting into several PDFs.
- Scan at a lower resolution next time: 150 to 200 dpi is plenty for reading on screen.
- Use a link instead of an attachment for very large files.
Is it safe?
The PDF is compressed inside your browser and never uploaded, so a payslip or a contract doesn’t pass through anyone’s server. If it’s confidential, add a password in the same Finish tab (AES-256 encryption) and send the password by a different route.