How to Split a PDF by File Size
Your PDF is too large for an email attachment or portal upload, but you can't just compress it small enough. The solution: split it into multiple files, each under your target size. OneClickPDF's Split by Size tool automatically divides your PDF so every chunk stays under the limit you set.
Updated 24 February 20261 min read4 steps
On this page · 3 sections
Step-by-Step Guide
Open the Split by File Size tool
Go to the Split by File Size page on OneClickPDF.Upload your large PDF
Drop the oversized file onto the upload zone.Set your target size
Enter the maximum file size per chunk (e.g., 5 MB for corporate email, 10 MB for Gmail, 25 MB for large attachments). The tool calculates how many chunks your PDF will produce.Split and download
Click Split. The tool divides your PDF into the minimum number of files, each staying under your target size. Download them all in a ZIP.
Frequently Asked Questions
How does it determine where to split?
The tool adds pages one by one to each chunk, checking the resulting file size. When adding another page would exceed the target, it starts a new chunk. This produces the fewest possible files.
Will every chunk be under the target size?
Yes, as long as no single page exceeds the target on its own. If a single page produces a file larger than the limit, that page becomes its own chunk.
Can I use this for email attachments?
Absolutely. Set the target to your email provider's limit (5 MB, 10 MB, or 25 MB) and each resulting file will fit as an attachment.
Does splitting affect quality?
No. Pages are copied losslessly using vector-based PDF manipulation. Text, images, and formatting are preserved exactly.
When compression isn't enough, size-based splitting guarantees each file fits your limit. Send multi-part attachments, upload in batches, or distribute sections individually.
