How to Compress a PDF for Email (Under 25 MB)

“The attachment is too large.” Almost everyone has hit this wall. Most email providers cap attachments at around 20–25 MB, and a single scanned document can blow past that easily. Here's how to get any PDF under the limit.

What the common limits actually are

• Gmail: 25 MB per email (and that includes the encoding overhead, so the real ceiling is closer to ~20 MB).
• Outlook / Microsoft 365: 20 MB by default.
• Yahoo Mail: 25 MB.
• Many corporate servers: 10 MB — stricter than the big consumer providers.

A safe target is under 10 MB. That sails through almost every inbox.

The fastest fix: compress it

1. Open PDFSqueeze and drop in your PDF.
2. Choose a compression level. Recommended works for most files; pick Strong if you need to squeeze under a tight limit.
3. Download the smaller PDF and attach it. Done — no sign-up, no upload.

Because image-heavy PDFs and scans are exactly the files that bust email limits, and image down-sampling is exactly what compression targets, the savings are usually large — often 50–80% smaller.

If it's still too big

A few extra options when one PDF just won't fit:

• Split it. Send chapters or sections across two emails.
• Compress harder. Use the Strong level — for documents you only need to be readable, lower image quality is a fair trade.
• Share a link instead.For genuinely huge files, upload to a cloud drive and email the link. But try compression first — it's faster and keeps the file in the message.

Why compress instead of uploading to a random site?

Email attachments are often sensitive — invoices, contracts, IDs. Many online compressors send your file to their servers to process it. PDFSqueeze does the whole thing in your browser, so the document never leaves your device. More on that in Is it safe to compress PDFs online?