Merge PDF

Combine several PDFs into one file, in whatever order you put them. The merging happens in this browser, on this computer — the files are not uploaded, because burrow has no server that could receive them.

This tool needs JavaScript

The merging is done by code running in your browser, so with JavaScript switched off there is nothing to do the work. There is no server-side version to fall back to — that is the whole design, not a missing feature.

With JavaScript on, this page lets you choose several PDFs, put them in the order you want, and download the combined file. Nothing is sent anywhere.

What happens to large files

Everything is held in this browser tab's memory, so the practical limit is what your device can spare rather than an upload size. burrow refuses a set of files totalling more than 512 MB before it opens any of them, and refuses an output of more than 10,000 pages before it writes any of them — so an oversized job is refused rather than failing part way through and leaving you with something incomplete.

The size limit is applied to what you chose, not to what has been loaded — burrow adds up the file sizes and refuses before it opens the first one, so an oversized selection is turned away immediately rather than after it has filled the tab.

What that does not save you from, said here rather than discovered: a very large merge that is under both limits can still make the tab slow while it runs, and on a phone the browser may stop the tab entirely. That is the device's memory ceiling, reached inside the PDF engine where nothing can intervene.

What is kept, and what is not

Pages, their contents and their sizes come across unchanged. Bookmarks, attachments and form fields are kept from the first file — later files contribute their pages. Merging outlines from several documents has no obviously right answer, so burrow does not guess at one.

A file that is encrypted, damaged, or not a PDF stops the whole merge. burrow will not quietly leave a file out: a combined document that is missing pages looks complete, and you would find out when you needed them.