Free Online Merge PDF Files
Combine multiple PDF files into one document, in the order you choose.
Files are combined in the order shown below. Use the arrow buttons to move a file up or down.
| # | File | Pages | Size | Order |
|---|---|---|---|---|
| No PDFs added yet. | ||||
Add at least two PDF files to begin.
About the Merge PDF Tool
Combining several PDF documents into one file is a common need: a report assembled from multiple chapters, a job application with a cover letter and portfolio, or a set of invoices that should be sent as a single attachment. This tool merges PDF files directly in your browser. The files are never uploaded, so contracts, medical records, and other confidential documents stay on your own device.
How the merge works
Each PDF is parsed with the open-source pdf-lib library. The tool reads every page from every source document in the order you choose, copies those pages into a brand new PDF, and writes a clean file with a fresh page tree. That means the result is a genuine PDF rather than a ZIP file renamed with a .pdf extension. Bookmarks, form fields, and annotations are not carried over by this page-copy method, but the visible page content, embedded fonts, and images are preserved.
Tips for a clean result
- Arrange before merging: Use the up and down buttons until the list matches the order you want in the final document.
- Check page counts: The table shows how many pages each file contributes, so you can spot a wrong or empty PDF before combining.
- Mixed page sizes: Pages keep their original dimensions. A merged file can contain A4, Letter, and landscape pages side by side, which is normal for PDF.
- Encrypted files: PDFs that require a password cannot be merged. Unlock your copy first, then merge the decrypted version.
Frequently asked questions
How many PDF files can I merge at once?
You can add up to 40 PDF files. Very large documents depend on your browser's available memory, so merging dozens of image-heavy files may be slow on older devices.
Are my PDFs uploaded to a server?
No. All reading, copying, and saving happens locally with JavaScript. Nothing is transmitted, stored, or logged by ImGenerate.
Why did my merged PDF lose bookmarks or form fields?
This tool copies pages into a new document. Interactive elements that live outside the page content, such as bookmarks, links, and AcroForm fields, are not recreated. The page appearance itself is retained.