The short answer: divide the PDF into page ranges that each land under ~18 MB, name the parts clearly ("Part 1 of 3"), compress each part, and send them as a numbered sequence of emails. The recipient can rejoin them in seconds if needed.
Splitting is the answer when compression alone can't get a file under the limit — the 300-page catalog, the full project archive, the scan collection that laughs at your compressor.
The workflow
1. Decide your split points
Aim for as few parts as possible, each comfortably under ~18 MB (the practical ceiling for Gmail/Outlook once encoding overhead is counted — see the limits explainer).
Split at natural boundaries, not arbitrary ones:
- Chapters or sections — the obvious choice for reports and books.
- Halves or thirds for uniform documents — pages 1–100, 101–200.
- By content type — the contract in one email, the appendices in another.
Avoid splitting in the middle of a section if you can. "Part 1 ends mid-sentence" is a small cruelty.
2. Split the file
In PDFEdit's split tool, use range mode:
- Part 1:
1-80 - Part 2:
81-160 - Part 3:
161-240
…adjusting to your actual boundaries. Each range downloads as its own PDF. The tool validates ranges as you type, so you can't request pages that don't exist.
3. Compress each part
Run every part through the compressor. This is the step people skip — and it's what turns three 20 MB parts into three 7 MB parts that sail through any mail server, including strict 10 MB corporate ones. Recommended preset is fine; the parts are already small.
4. Name and send
Name files so the recipient never has to guess:
Project-Name-Part-1-of-3.pdfProject-Name-Part-2-of-3.pdfProject-Name-Part-3-of-3.pdf
In the email(s), say what you did: "The full report was too large to attach, so I've split it into 3 parts — all attached across these emails, in order." If parts go in separate emails, number the subject lines: "Q3 Report (1 of 3)."
How many parts is too many?
Two or three parts: totally fine, recipients handle it easily. Four or five: acceptable for a big archive, but include a one-line index. More than five: stop — at that point a cloud link (Drive, OneDrive, Dropbox) is the better answer. Nobody wants seven emails titled "Archive (4 of 7)."
Alternatives worth considering
- Compress harder instead. If splitting feels like overkill, try the Extreme compression preset first — it cuts 60–85% and might make splitting unnecessary.
- Cloud link. For files over ~100 MB, or when the recipient needs the whole thing as one file, upload and link. Gmail/Outlook both offer this automatically at the limit.
- WhatsApp/Telegram. For informal sharing, their 2 GB document limits swallow anything email can't.
The recipient can rejoin
If someone needs the single file back, it's trivial: add the parts to a merge tool in numbered order and download the recombined PDF. Merging is lossless, so the rejoined file is identical in content to the original. Mention this in your email — "you can rejoin them with any free PDF merger" — and you'll preempt the reply asking for "the whole thing as one file."
What to write in the email
The emails matter as much as the files. A good multi-part email sequence:
Subject lines: Q3 Financial Report (1 of 3), (2 of 3), (3 of 3). The parenthetical does the work — the recipient instantly knows the shape of what they're getting.
Body (first email):
Hi [name] — the full report was too large to send as one attachment, so I've split it into 3 parts, attached across 3 emails in order. Each part is also compressed for quick downloading. If you'd prefer it as a single file, I can share a download link instead — just let me know.
Body (subsequent emails): one line is enough: "Part 2 of 3 attached."
This preempts the two replies you'd otherwise get: "is this the whole thing?" and "can you send it as one file?"
When not to split
Splitting is a packaging compromise. Skip it when:
- The recipient needs to search the whole document. Three separate PDFs means three separate searches. A cloud link to one file is better.
- Page references matter. "See page 47" breaks when the document is in parts. Either add a note mapping parts to page ranges, or keep it whole via link.
- It's a formal submission. Splitting a tender response or application across emails looks disorganized. Compress hard, or use the portal's uploader.
- More than ~4 parts. At that point the email sequence is worse than every alternative. Link it.
Split points that work well
The best splits follow the document's own structure:
- Reports: by chapter or section heading.
- Invoices/receipts: by month or by client.
- Books/manuals: by part or chapter.
- Mixed bundles: by document — contract in one email, appendices in another.
The worst splits are purely arithmetic (pages 1–67, 68–134) with no regard for content — acceptable when the document is uniform (a photo archive), but try to respect structure when it exists. And always split between sections, never mid-sentence: ending Part 1 in the middle of a paragraph is a small but real annoyance.
Do it with PDFEdit
Split the large PDF by range, compress each part, and you're done — all free, all in-browser, no uploads. The batch merge page handles rejoining many parts at once.
The bottom line
Splitting for email is a packaging job: natural boundaries, clear names, compressed parts, numbered emails. Keep it to three parts or fewer; beyond that, send a link. Either way, the recipient gets a complete, readable document — which is the entire point.
