How to split a large PDF to send it by email
Gmail lets you attach up to 25 MB, Outlook 20 MB, and many online forms only accept files of 5 or 10 MB. A scanned PDF or one full of photos goes over that limit fast.
Shinobi.pdf’s “Size” mode splits the PDF into parts that don’t exceed the size you choose, without ever cutting a page in half.
Step by step
Open the PDF
Drop it onto Shinobi.pdf or right-click it in File Explorer → “Split with Shinobi.pdf”.
Choose the “Size” mode
Type the “Maximum size (MB)” for each part: for example 24 for Gmail, to leave some margin.
Check the estimate
Shinobi.pdf shows the PDF’s size and roughly how many files you’ll get.
Turn on “Compress”
It makes each part smaller without losing quality.
Click “Split PDF”
The parts are numbered so they can be put back together in order.
Tips
- If a single page is bigger than the limit (a huge photo, for example), it ends up alone in a slightly larger file: a page can’t be split.
- Whoever receives the parts can merge them back with Shinobi.pdf’s “Merge”.
Frequently asked questions
How many MB should I use for Gmail?
Gmail accepts 25 MB per email. Use 24 to be safe, and send each part in its own email.
Does it reduce quality?
No. Pages are copied as they are, and “Compress” only tidies up and optimizes the file: it doesn’t lower image resolution.
What if I’d rather split every few pages?
Use the “Every N” mode: it creates a file every number of pages you choose.
