Split by Size
Split a PDF into parts that fit an email attachment limit.
About this tool
Split PDF by File Size — Fit Any Email Attachment Limit
Cut a large PDF into parts that each stay under a size you choose, such as 25 MB for Gmail. Everything runs locally in your browser — no upload, no sign-up, no watermark and no file size limit.
Set a Size Limit
Enter a maximum in megabytes or pick a Gmail or Outlook preset; pages are packed into as few parts as possible.
Measured, Not Guessed
Each part is actually built and measured, so shared fonts and images are counted correctly and no part goes over the limit.
One ZIP, Page Order Kept
Parts are numbered in page order and delivered together in a single download.
How to use it
- Drop the large PDF you need to send.
- Type the maximum size per part in megabytes, or tap a preset: Gmail · 25 MB, Outlook · 20 MB, 10 MB or 5 MB.
- Click Split by size. Each part is built and measured on your device, so no part ends up over the limit.
- Download the ZIP with the numbered parts. If the whole file already fits, you get a single PDF and the result says it is already under the limit.
Frequently asked questions
Are my PDFs uploaded to a server?
No. Toolula processes the document inside your browser tab with pdf-lib and WebAssembly, so the file never leaves your device.
What if one page is bigger than my limit?
A single page cannot be split further. It is placed in its own part and flagged so you can compress it first.
Why leave headroom below the email limit?
Email encodes attachments, which makes them roughly a third larger, so a 20 MB part can exceed a 25 MB cap.
Are the parts compressed?
No. Pages are copied as they are, so quality stays the same. If you would rather send one smaller file than several parts, use Compress PDF instead.
Is it really free?
Yes. You can use every Toolula PDF tool for free, without an account. The free plan has fair-use limits; Toolula Pro, an optional plan, raises them and adds advanced features.