Split a PDF by File Size
A 50MB PDF won't fit in Gmail (25MB limit), and most submission portals have their own caps. Split by Size automatically divides a large PDF into chunks that each fit under your chosen limit. No guessing where page breaks should be — the tool calculates optimal split points based on each page's contribution to file size.
How to Split a PDF by File Size
- 1Load the large PDF
Drop your oversized PDF into the split tool. The tool analyzes the file and shows its total size and page count. You can see which individual pages are contributing the most to file size.
- 2Set the target maximum size per file
Enter your desired size limit, such as 25MB for Gmail, 20MB for Outlook, 10MB for a submission portal, or 5MB for a specific upload system. The tool shows how many files the split will produce.
- 3Split the PDF
Click split. The tool divides the PDF at page boundaries to create files that each stay under your size limit. Pages with high image content may get their own file. Processing is local.
- 4Download all parts
Download each split file individually, or download all as a ZIP archive. Files are named sequentially: Filename-part-1.pdf, Filename-part-2.pdf, etc. Check that each file opens correctly and is under your specified size limit.
Split by size now
Break large PDFs into email-friendly chunks. Done in your browser.
Split by Size NowFrequently Asked Questions
How does the tool decide where to split?
The tool measures the file size contribution of each page, then finds optimal page boundaries that keep each chunk under your limit. It divides as evenly as possible. Pages with large images may end up isolated if their individual size exceeds the limit.
What if a single page is larger than my size limit?
The tool can't split a single page across multiple files. If any individual page exceeds your limit, compress the PDF first to reduce page sizes, then try splitting again. The compress tool is designed for this scenario.
Will the split affect the quality of each part?
No. Splitting by size copies pages directly from the original. Each part has the same quality, resolution, and formatting as the original file. No re-compression or quality changes.
Can I specify a different size limit for each part?
The tool applies one size limit to all output parts. If you need variable sizes, run multiple split operations with different limits and manually combine the files you want.
Your document stays on your device
Size-based splitting runs entirely in your browser. The large PDF and all its parts are processed locally. No file data is ever uploaded to any server.