Email bounced because your PDF is too big? Here is how to shrink a PDF under common attachment limits like 10 MB or 25 MB — free, online, without losing readable quality.
Why your PDF is too big to email
Most email providers cap attachments: Gmail and Yahoo allow 25 MB, Outlook 20 MB, and many company mail servers stop at 10 MB. Scanned documents are the usual culprit — each page is stored as a full-resolution photo, so a 20-page scan can easily pass 30 MB.
Compression re-encodes the images inside the PDF at a smarter quality level. Text stays sharp, because text in a real PDF is stored as vectors, not pixels.
Compress the PDF in three steps
Open the free Compress PDF tool and drop in your file.
Pick a level: “recommended” balances size and quality; “extreme” gets the smallest file for scans you only need to be readable.
Download the compressed PDF and attach it — most files shrink 40–80%.
Still over the limit?
If one file must stay large, split it into parts and send them across two emails, or extract just the pages the recipient needs with the Extract Pages tool.
For recurring large documents, compress before scanning: set your scanner to 150 DPI grayscale instead of 600 DPI colour — the PDF will start out several times smaller.
Does compressing reduce quality?
On the recommended setting the difference is barely visible on screen or in print at normal sizes. Only heavily compressed photos (the “extreme” setting) show softening — text remains crisp either way.