Merge PDF
Join several PDFs into one document in the order you choose, entirely in your browser. Handy for assembling a single submission from separately signed pages, or for stitching scanned chapters back into one file.
How to merge PDF files
Add all the PDFs you want to combine.
Drag them into the order you want.
Merge and download the single combined PDF.
Order is the whole job
Merging is mechanically simple and easy to get wrong in exactly one way: sequence. Set the order deliberately before you merge, especially when filenames sort alphabetically rather than logically — "appendix.pdf" lands before "chapter1.pdf" in any alphabetical list, which is almost never what you want.
If the parts came from a scanner that split a document into batches, check the seam pages after merging. A duplicated or missing page at a batch boundary is the most common scanning error and the easiest to miss.
What survives the merge
Page content comes across exactly: fonts, images, layout and any selectable text layer are preserved, because pages are copied rather than re-rendered. A merged document remains searchable if its sources were.
Document-level features are less portable. Bookmarks, form fields and annotations vary in how well they carry across depending on how each source PDF was produced. If a source relies heavily on interactive form fields, check them in the merged file before sending it on.
File size and practical limits
The merged file is roughly the sum of its parts, so combining several image-heavy PDFs produces something large. If the result needs to be emailed, run it through Compress PDF afterwards rather than compressing each part first — one pass over the finished document is more effective.
There is no fixed page or file limit here because nothing is uploaded. Very large merges depend on your device's available memory, which is generally more generous on a laptop than on a phone.
Mixing scanned and digital sources
Merging a digitally created PDF with a scanned one produces a document where some pages have selectable text and others are pictures of text. It looks consistent and behaves inconsistently: searching finds hits in half the document and silently misses the rest.
If the merged file needs to be searchable throughout, run the scanned parts through the PDF OCR tool before merging. Doing it first is much easier than working out afterwards which pages were the scanned ones.
Checking the result before you send it
Open the merged file and check three things: the total page count matches the sum of the parts, the seams between documents land where you expect, and nothing has been duplicated at a boundary. Those three checks catch nearly every merge error.
Page count is the fastest signal. If twelve plus eight produces nineteen pages, a page was dropped, and finding it now is far easier than after the document has been signed, circulated or filed.