Guide

How to split and merge PDFs

Break a big PDF into separate files, or join several PDFs into one, without re-compressing the pages or dropping the document's metadata. Here is the clean way to do both.

These are page operations, not edits

Splitting and merging never touch the content of a page, so they always work (even on scans) and the result is byte-for-byte the same pages, with the metadata carried over. In pdfblah they live under Tools, each with its own inputs.

Split one PDF into several

1. Open pdfblah.com, drop in your PDF, and switch to Tools → Split.
2. Choose how to cut it: one file per page, every N pages, or by page ranges (for example 1-3, 4-6 to make two files).
3. Download the pieces as a zip.

Merge several PDFs into one

1. Open Tools → Combine.
2. Your uploaded PDF is first; add the others and drag them into the order you want.
3. Download the single combined PDF.

Three ways to do it

Same engine every way, so the result is identical. Pick whichever fits:

• Online at pdfblah.com — nothing to install, free while we're testing.
• On your machine, free and private (nothing is uploaded): pip install pdfblah, then pdfblah gui opens the same tool in your browser.
• Command line, for scripts and bulk jobs:

pip install pdfblah

# split into one file per page
pdfblah split in.pdf -o parts/ --every 1

# split into custom groups: pages 1-3 in one file, 4-6 in another
pdfblah split in.pdf -o parts/ --ranges 1-3 4-6

# merge several PDFs, in order, into one
pdfblah combine cover.pdf body.pdf appendix.pdf -o whole.pdf

The app and CLI are open source (MIT). See the pdfblah project on GitHub.

Related page tools

pdfblah can also keep or reorder pages (pdfblah pages in.pdf out.pdf --keep 3,1,2), rotate them (pdfblah rotate in.pdf out.pdf --degrees 90), and crop the page area, all without re-rendering the content.