Merge PDF Files

What this tool does

You add two or more PDF files, put them in the order you want, and the tool joins them into one document called merged.pdf. Pages from the first file come first, then the second, and so on. The work happens in your browser with the pdf-lib library; the files are not uploaded to a server.

Step by step

1. Choose your PDFs. You can use the picker more than once to keep adding files.
2. Use the up and down arrows to set the order, or the X to remove a file.
3. Click Merge PDFs, then Download. The result shows the total page count and file size so you can sanity-check it.

Good to know before you rely on it

• Password-protected PDFs are refused. The tool names the file that is protected. Open it in a PDF viewer, remove the password, save a copy and add it again.
• Page content is copied as it is: text, images, fonts, vector graphics and page sizes. Document-level extras such as bookmarks (the outline panel) and interactive form fields may not survive, so check the result if your documents depend on them.
• Memory limits. Everything is held in memory on your device. A handful of ordinary files merge quickly; dozens of very large scans can be slow or fail on a phone.
• Damaged files that are not valid PDFs produce an error naming the file instead of a broken output.
• Merging the same file twice is allowed, which is a quick way to repeat a page set.

Typical uses

Combining a cover letter, resume and certificates into one application, joining scanned pages from several sessions, or assembling invoices for one month. To pull pages back out later, use the Split PDF tool.

Keeping the file small

The output is about the size of the inputs added together. This tool does not compress. If the merged file is too large for an email or upload form, compress the source files first.