Split a PDF into parts by file size
When a PDF is too big to attach and you don’t want to lose quality by compressing it, split it instead: set the maximum size per part and the tool distributes the pages into as few files as possible, each under the limit — part 1, part 2, part 3… Pages are copied as they are, so nothing gets recompressed or degraded. Works entirely in your browser.
How to use the Split PDF by size tool
Select or drag your PDF.
Enter the maximum size per part in MB (e.g. 10 for most email services).
Click “Split by size” and download the parts (ZIP).
Your files stay on your device
This tool runs entirely in your browser using JavaScript and WebAssembly. There is no upload step and no server processing — open your network panel and check: zero document data is transmitted. It even keeps working offline once the page has loaded.
Frequently asked questions
Split or compress — which should I use?
Compress when the recipient needs a single file and some quality loss is acceptable. Split when quality must stay intact (contracts, scans for official use) or the file is far above the limit. You can also compress first and split the result.
Can a single page be bigger than the limit?
If one page alone (for example a huge scanned image) exceeds the limit, it becomes its own part — it can’t be split further. Run that file through Compress PDF to size if it must fit.
How do I put the parts back together?
Use the Merge PDF tool: add the parts in order and you get the original document back, unchanged.
Is it safe to use this tool with confidential documents?
Yes — and verifiably so. PDFAgent has no upload step: your file is processed by JavaScript running in your own browser and never leaves your device. You can open your browser’s network panel (or even go offline after loading the page) and confirm that no document data is transmitted.