Merge PDF
Combine multiple PDF files into one document in the exact order you choose. Runs entirely in your browser.
How to use this tool
- Click or drag PDF files into the dropzone.
- Reorder them using the up and down buttons next to each file.
- Click Merge PDF — processing takes a few seconds for average files.
- Download the combined PDF.
How it works
Each selected PDF is parsed with PDF-lib. The pages of every document are copied into one output PDF in the order you arranged them, then written back to a downloadable Blob.
Tips
- Merge files with the same page size for a cleaner result — mixed sizes keep their own dimensions.
- Keep total size reasonable; very large files can slow the browser.
Limitations
Merging happens in memory, so extremely large files (over ~1 GB) or many large PDFs may exceed browser memory and fail.
Frequently asked questions
Is merging PDFs really free?
Yes. The tool runs entirely in your browser with a free open-source library, no account and no watermark.
Does this keep the quality of my PDFs?
Yes. Pages are copied into the new document, so text stays selectable and quality is preserved.
How many PDFs can I merge?
As many as you like, though large files consume browser memory. Files of a few hundred MB work fine on a desktop browser.
Are my documents uploaded anywhere?
No. Everything is processed locally with PDF-lib inside your browser tab.