Split PDF by file size
Set a target maximum file size (e.g. 10 MB) and PDF Lab splits the document into as many parts as needed to stay under that limit — all processed locally.
or drop files here
Tip: select a single file.
How to use Split by Size
- 1Click "Select PDF file" and choose the PDF you want to split.
- 2Enter a maximum file size per chunk (e.g. 5 MB) or a fixed number of pages per part.
- 3Click Split PDF. The resulting parts are generated locally and downloaded as a ZIP.
Why use PDF Lab
- Divide a large PDF into smaller chunks by file size or fixed page count.
- Files stay on your device — nothing is uploaded to any server.
- No account, no signup, no watermark on the output.
- Free to use with no per-file limits beyond your device's memory.
- Works on desktop and mobile browsers, including offline after first load.
- Useful for meeting email attachment limits or upload size caps.
- Each chunk is a fully valid, self-contained PDF.
Your file never leaves your browser
Split by Size runs entirely on your device using pdf-lib and pdf.js — both self-hosted by PDF Lab, so no third-party CDN sees your traffic. There is no upload, no account, no log of your file.
How browser-based PDF processing works →Split by Size — questions
- No. Every operation runs in your browser using JavaScript. Your file is loaded into your browser's memory, processed, and a result is saved to your device. Nothing is sent over the network.
- No. Because the processing happens in your browser, neither PDF Lab nor any third party has access to the file contents. You can verify this by opening your browser's network tab while using the tools — no file data is transmitted.
- There is no enforced limit, but performance depends on your device's memory. Most modern browsers comfortably handle PDFs up to about 100 MB. Very large files may slow down your browser tab.
Are my files uploaded to your server?+
Can PDF Lab see the contents of my files?+
Are there file size limits?+
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