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About this tool
A closer look at Merge PDF
Merge PDF combines two or more PDF files into a single document. Each source file is opened in browser memory and its pages are copied into a new PDF in the order you set — you can reorder the file list before processing, and duplicate files (same name, size and modified time) are skipped automatically so pages are not doubled by accident.
Use it when you are assembling a bundle: a set of receipts for an expense claim, several weeks of statements, signed documents gathered from different people, or chapters of a report that were prepared separately. This is the first tool to reach for whenever you need one PDF instead of many.
The merge copies the original page objects rather than rendering pages into images, so text stays selectable, vector graphics stay sharp and the file does not grow from re-encoding. The merged PDF is built in your browser and offered as a local download; no part of any source file is transmitted to a server.
Supported files
How to use it
- 1Select PDFs from your device
- 2Reorder files before processing
- 3Download the merged file instantly
What you can use it for
- Combining invoices, receipts or bank statements into one document for record-keeping.
- Joining separate PDF chapters or pages into a single file before sending or printing.
- Assembling a consolidated PDF from files shared by different teammates.
- Merging multiple signed pages that were returned as separate scans.
- Creating one printable PDF from several document exports before filing.
What to keep in mind
- Every source file must be a PDF; images and Word documents cannot be added to the merge directly.
- Password-protected PDFs must be unlocked first with Unlock PDF, otherwise their pages cannot be read.
- Duplicate files detected by name, size and modified time are skipped automatically.
- Very large PDFs (above 100 MB) are processed in browser memory and may be slow on low-memory devices.
- Ordering happens per file, not per page — to reorder pages within a file, use Organize PDF first.
Troubleshooting
One of the files will not merge
Confirm it is a real PDF (not an image renamed to .pdf) and that it is not password-protected. Unlock encrypted files first, or re-export the page as a PDF.
Pages appear doubled in the output
You likely added the same file twice without noticing. Duplicate detection is based on name, size and modified time, so check the list and remove repeat entries.
The merged file is very large
Merge preserves original pages, which is intentional. Run Compress PDF on the result afterwards if you need a smaller file for email.
Related tools
Frequently asked questions
Can I change the order of files before merging?
Yes. Reorder the files in the list before merging — pages are copied into the output in the order shown.
What happens if I add the same PDF twice?
Duplicate files (same name, size and modified time) are skipped automatically so you don't end up with doubled pages.
Does merging change page quality?
No. RookPDF copies the original page objects into the new file rather than re-rendering them, so text stays selectable and vector graphics stay sharp.
Does merging upload my documents?
No. Files are opened in browser memory, combined locally, and the merged PDF is saved as a download.
Can I merge password-protected PDFs?
Unlock them first with the Unlock PDF tool, then add the unlocked files to the merge.
What if a source file looks corrupted or is not a PDF?
Invalid or unsupported files are ignored or rejected before merging; check the file list and re-export the PDF from the application that created it.