Merge PDF
Combine several PDFs into one, in the order you choose.
Drop your PDFs here
They are combined in the order shown below · nothing is uploaded
No PDFs added yet
Add two or more PDFs and they will be joined into a single document, in the order you choose.
Private by design. This tool runs entirely in your browser. Your file is processed on your own device and is not uploaded by DO101.
About the Merge PDF
Drop in as many PDFs as you need, drag them into the right order, and download a single combined document. The merge happens with pdf-lib inside your browser, so even a confidential contract never leaves your device.
How to use it
- 1Add two or more PDFs.
- 2Use the arrows to put them in the right order.
- 3Press merge and download the combined PDF.
What you get
- Unlimited files, merged in your chosen order
- Page counts shown before you merge
- No watermark and no page limit
- Original quality — pages are copied, not re-rendered
- Runs entirely in your browser
Frequently asked questions
Are my PDFs uploaded anywhere?
No. Merging is done by pdf-lib running inside this page. There is no upload endpoint behind this tool, so the files physically cannot reach a server.
Is there a limit on how many files I can merge?
There is no fixed limit. The practical ceiling is your device's memory — a few hundred megabytes of PDFs is comfortable on a laptop, less on an older phone.
Does merging reduce quality?
No. Pages are copied across intact, so text stays selectable and images keep their original resolution.
Can I merge password-protected PDFs?
No. Encrypted PDFs cannot be opened in the browser. Remove the password in the app that created the file first.
Keep going
People who use this tool usually reach for these next.
Break one PDF into separate files by page count or range.
Make a PDF smaller, with an honest choice about the trade-off.
Put a PDF's pages into a different order.
Any mix of image formats into one PDF.