Merge PDF files
Combine PDF files into one document, in the order you choose. Everything happens in your browser, so your files are never uploaded.
Drop your PDFs here
or tap to choose files · they stay on your device
Drag to reorder, or use the arrows. Use the arrows to reorder. The merged file follows this order.
Add at least one more file to merge.
Loading engine…
Your files have not left this device.
Merged
Download merged PDFHow it works
Your browser downloads pdf-lib, a PDF toolkit written in JavaScript, and runs it locally. It builds a new document and copies the pages of each of your files into it, in the order you set.
Copying is the important part. Pages are moved across as they already are, not re-rendered or re-encoded, so text stays selectable, images keep their original resolution, and page sizes and orientation survive exactly. A merged file is therefore about as large as its parts added together. If you need it smaller, compress the result afterwards.
Because the work happens on your device, there is no upload, no queue, and no server holding your documents.
Questions
Can I choose the order the files are joined in?
Yes. Once you have picked your files, drag them into the order you want, or use the up and down buttons on each row. The merged document follows the order shown in the list, top to bottom.
Are my PDFs uploaded to a server?
No. The merging happens inside your browser using pdf-lib, which your browser downloads once and then runs locally. Your files never leave your device, so we cannot see them. Once the page has loaded, merging works offline too.
Does merging reduce quality or make the file smaller?
Neither. Pages are copied across as they are, not re-rendered, so text stays sharp and images are untouched. That also means the merged file is roughly the sum of its parts. If you need it smaller afterwards, run it through the compress tool.
How many files can I merge, and how large?
There is no fixed limit. The work happens in your device’s memory, so your hardware is the ceiling. A few hundred megabytes of input is comfortable on a typical laptop; a phone or an older machine will manage less. The tool warns you when the total gets large.
What happens to bookmarks and form fields?
Page content, page sizes, and orientation all carry across exactly. Document-level extras such as bookmarks, the table of contents, and interactive form fields are not copied, so the result is a clean set of pages rather than a rebuilt interactive document.