Merge PDF Files
Combine two or more PDFs into a single document — reorder before merging, all in your browser.
🔒 Processed locally in your browser. Nothing is uploaded.
Upload PDFs
Drop PDFs here or click to select
Add two or more PDFs. Order can be changed below.
How to merge PDFs
- Click the drop zone above, or drag your PDFs directly into it.
- Add at least two files. The order shown is the merge order.
- Drag a file card up or down to change its position in the merged PDF.
- Click Merge PDFs. Processing happens in your browser.
- When the download prompt appears, save the merged file to your device.
Technical limitations
- Encrypted PDFs. Password-protected files cannot be merged directly. Unlock them first with our Unlock PDF tool.
- Memory limit. Very large merges (hundreds of MB) may fail on older devices. If that happens, try merging in batches.
- Bookmarks and forms. Existing PDF bookmarks and form fields are not preserved by pdf-lib during merge. Page content and text are preserved faithfully.
- Signatures. Digital certificate signatures (not visual stamps) are invalidated by any modification, including merging. This is true of every PDF tool.
Frequently asked
Is there a limit on how many PDFs I can merge?
No hard limit — the practical limit is your device's available memory. Most laptops handle 20–50 files fine.
Are my PDFs uploaded anywhere?
No. Everything runs locally in your browser using pdf-lib. Disconnect from the internet and it still works.
Can I change the order of files?
Yes — drag any file card up or down before clicking Merge.
What about password-protected PDFs?
They cannot be merged directly. Unlock them first using the Unlock PDF tool.