Is there a file size limit when merging PDFs?

No server-imposed limit — because it runs locally, the only constraint is your device's memory.

Are my PDFs uploaded when merging?

No. Everything happens on your device; your files are never sent to a server.

How to merge PDF files

Need to combine a contract, invoice and cover letter into one file? Here's how to merge PDFs privately, with full control over order.

Open Merge PDF

Steps

Open the merge PDF tool and add your files.
Drag or use the arrows to set the order pages appear in.
Click merge — the document is assembled in your browser with pdf-lib.
Download the combined PDF instantly.

No limits, nothing uploaded

Because merging happens locally, there's no file-size or page-count cap beyond your device's memory, and sensitive documents never touch a server. Need the opposite? Use the split tool to pull pages back out.

Tools used in this guide

Merge PDFCombine multiple PDFs into one Split PDFSplit a PDF into pages or ranges Compress PDFReduce PDF file size