PDF too large for email: split it and send
Your mail provider refuses the attachment? Split the document into parts that each fit under the limit. The number you need to work from is megabytes, not pages.
What mail providers really allow
The limit applies to the whole message including encoding overhead, so the real ceiling is always a bit lower than advertised. Aim for about 80% of the figure in the table and your message will go through.
| Provider | Attachment limit | Safe part size |
|---|---|---|
| Gmail | 25 MB | 20 MB |
| Outlook.com | 20 MB | 16 MB |
| Yahoo Mail | 25 MB | 20 MB |
| Corporate Exchange | often 10 MB | 8 MB |
| iCloud Mail | 20 MB | 16 MB |
How to work out pages per part
The arithmetic is simple. Divide the file size by your target part size to get the number of parts. Then divide the total page count by that number and round down.
Example: a 120 MB document with 400 pages has to go through Gmail. 120 ÷ 20 = 6 parts. 400 ÷ 6 ≈ 66, so set 60 pages per part — that gives seven parts with room to spare.
This works when pages weigh roughly the same. If the document contains a few heavy scans, leave a bigger margin and check the size shown next to each finished part.
Why splitting beats compressing
Compression trades quality for size: text survives, but scans and photographs visibly lose sharpness. For a contract with stamps or a technical drawing that is often unacceptable.
Splitting does not touch the content at all — pages are copied as they are. The recipient gets the same quality, just across several messages.
When to send a link instead
If you end up with more than five or six parts, the message becomes a nuisance for the recipient. In that case a cloud link is kinder, and splitting is better kept for cases where external services are forbidden or the recipient only works with email.
Questions & answers
Can I send all parts as one archive?
You can — “Download all (ZIP)” packs them into a single file. But the archive weighs the same, so it will not fit the limit either; ZIP is handy for delivering the parts some other way.
Why do the parts together weigh more than the original?
Each part is a standalone PDF with its own structure and embedded fonts. A small increase per file is normal.
Can I know a part’s size in advance?
Not exactly, because pages differ in weight. After splitting, however, the size is shown next to every part, so you can check and re-split with a different number if needed.
Can the recipient put the document back together?
The parts open as ordinary PDFs in any reader. To merge them back into one file they would need a PDF merge tool.