Merge PDF Files Online Free — Your Files Are 100% Secure
Combine multiple PDFs into one document online for free. Secure and private — no signup, no watermark, no file limits.
Drop PDF files here
or
Max 25 MB per file · Secure and private — files are never stored
How it works
- 1Drop your PDF files into the box (or click to select them)
- 2Drag the files to set the exact order you want
- 3Click "Merge PDFs" — everything happens on your device
- 4Download your combined PDF instantly
Frequently asked questions
Are my files uploaded to a server?
No. FileCPU runs entirely in your browser. Your PDFs are read from disk into memory, merged locally, and handed straight back to you as a download. Nothing is ever transmitted or stored.
How many PDFs can I merge at once?
As many as you like, within two limits: each file can be up to 25 MB, and the combined document can have up to 200 pages. These limits exist because all the work happens in your browser's memory.
Can I choose the page order?
Yes — that is the whole point. Drag files up and down in the list (or use the arrow buttons) before merging. The output follows your order exactly: all pages of file 1, then file 2, and so on.
What about password-protected PDFs?
They cannot be merged. Unlock them first (with the password you own), then add the unlocked copies. FileCPU tells you which file is protected instead of failing silently.
Will bookmarks and form fields survive the merge?
Page content, text and images are preserved exactly. Interactive extras like bookmarks, form fields and annotations are not carried over — the output is a clean document.
Is it really free?
Yes. No accounts, no watermarks, no "premium" tier, no daily limits. Your browser does the work, so it costs us nothing to serve you.