Free · Private · In your browser

Merge PDF

Add two or more PDFs, drag to reorder, then merge into one file.

Drop your files here, or click to browse
Processed on your device — nothing is uploaded

How your files are handled

We built these tools so you never have to wonder where your documents go. Here is exactly what happens when you use them.

  • Your files are processed entirely in your browser using open-source libraries (pdf-lib, PDF.js, and others).
  • Nothing is uploaded to our servers. We have no backend that receives, stores, or scans your documents.
  • We cannot see, store, or access your files — not during processing, not after, not ever.
  • Processing uses your device's memory and CPU. Large files may take longer, especially on phones and tablets.
  • All tools are free with no paywall tricks, no hourly task limits, and no watermarks on your output files.

How it works

Three simple steps. Your files never leave your device, and the result downloads straight to your computer or phone.

Frequently asked questions

Common questions about privacy, pricing, and how these tools work.

More organize tools

Other free PDF utilities that work the same way — private, in-browser, no sign-up.

How to merge PDF

Merge PDF combines two or more separate PDF files into a single document, in the exact order you choose. It is handy for stitching chapters, scanned pages, or a set of invoices into one file.

  1. Drop two or more PDFs onto the page or click to browse; they load right in your browser and are never uploaded.
  2. Drag any file by its grip handle, or use the up and down arrows, to set the order the files will appear in.
  3. Add more files or remove any you do not need, then click Merge PDFs.
  4. Preview the combined result and download the single merged PDF.

Everything happens in your browser — your file is never uploaded, and there is no sign-up, watermark, or limit.

Frequently asked questions

Are my files uploaded to a server?

No. Every tool runs entirely in your browser using open-source libraries, so your file is processed on your own device and is never uploaded. We have no backend that receives, stores, or scans your documents.

Is it really free, and will there be a watermark?

Yes. There is no account, no sign-up, and no hourly limit, and the tools never add a watermark to your output. UnboundPDF is free and is not affiliated with Adobe.

Does it work on a phone or tablet?

Yes. The tools run in any modern mobile browser as well as on desktop. Because the work uses your device's own memory and processor, very large files simply take longer on phones.

Is there a limit on how many PDFs I can combine?

There is no fixed limit. You can add as many files as your device's memory can handle; the tool just needs at least two valid PDFs to merge.

Will the pages stay in the order I set?

Yes. Files are merged top to bottom in the order shown on screen, and every page from each file is kept.

Can I merge a password-protected PDF?

Not directly. An encrypted file is flagged so you can unlock it first with the Unlock PDF tool, then add the unlocked copy to the merge.