How to compress a PDF for email
Most email services cap attachments at 20 to 25 MB, and many company mail servers stop at 10 MB. A scanned contract or a report full of photos can blow past that easily. This guide shows how to get a PDF under the limit while keeping it readable.
Last updated November 2, 2026 · 4 min read
Know the limit you are aiming for
- Gmail: 25 MB per message, including every attachment.
- Outlook.com and Microsoft 365: 20 MB by default; many companies set it lower.
- Yahoo Mail: 25 MB.
- WhatsApp and Telegram documents: far larger, but recipients on mobile data will thank you for a small file.
- Government and job portals often allow only 2 to 5 MB. Check the form before you compress.
Why PDFs get big
Text itself is tiny. Almost all the weight in a large PDF comes from images: scanned pages stored as high-resolution pictures, photos pasted into a report, or screenshots at full screen size. Embedded fonts add a little, but images are the lever that matters.
That is why a good compressor works on the images inside the file rather than on the file as a whole. It re-encodes each picture at a sensible resolution and quality, and leaves text, links and bookmarks untouched.
Step by step
- Open the Compress PDF tool and drop in your file. Nothing is uploaded; the work happens inside your browser.
- Start with the Balanced level. It re-encodes images at a quality that looks identical on screen and usually cuts the size by half or more.
- Check the result size shown on the result card. If it is still too large, run the file again with the Strong level, which lowers image resolution to what a screen or a normal printer needs.
- For huge scans, use Extreme. It rasterizes each page, which gives the smallest possible file but turns text into images, so recipients can no longer select or search the text.
- Download the compressed copy and attach it. Keep your original; the compressed version is for sending, not for archiving.
If it is still too large
Split the document. The Split PDF tool can cut a long file into parts by page range so you can send two attachments or only the pages that matter.
Remove pages nobody needs. Organize PDF lets you delete cover sheets, blank scans and appendices before you send.
For files over 100 MB, a shared link from your cloud storage is more reliable than any attachment, and the recipient's mailbox will not fill up.