Merge PDF files
Combine two or more PDFs into a single file, in whatever order you choose.
How it works
- Click to browse or drag and drop two or more PDF files onto the page.
- Drag the file thumbnails to put them in the order you want them merged.
- Click Merge PDFs.
- Your combined file downloads immediately — nothing is ever sent to a server.
How this is different from any other PDF tool
Those tools merge your PDFs on their own servers — upload, process, download, then delete the file after a set window (an hour, a day). That's a real privacy practice, but it still means your file left your device at some point. FatafatPDF's merge runs entirely with WebAssembly in your browser tab: there's no upload step to encrypt or delete later, because the file never leaves your device in the first place.
Is it really free?
Yes — merging is free to use, right in your browser, with no file size cap (merging happens on your own device, so the ceiling is its memory, not a rule we set).
Is there a limit to how many PDFs I can merge?
You can merge several PDFs in one batch. Very large batches are limited mainly by your device's own memory, since everything runs in your browser.
Can I reorder pages before merging?
Yes — drag the thumbnails or use the arrow buttons to put your files in whatever order you need before merging.
Do the merged files need to be the same page size?
No — pages keep their original size and orientation. A mix of A4, Letter, and even landscape pages will merge fine; each page in the output keeps its own dimensions.
Does merging affect bookmarks or metadata?
The merged file is built fresh from the pages of your source files, so existing bookmarks and per-file metadata (like author or title) from the originals aren't carried over. Use Edit PDF Metadata or Create PDF Bookmarks afterward if you need those.
Can I merge very large PDF files?
Yes — there's no file size cap imposed by the tool, since merging happens on your own device instead of a server with an upload limit. Very large files (hundreds of megabytes, or documents with thousands of pages) will simply take longer and use more of your browser's memory; the ceiling is your device, not a rule we set.
Is it safe to merge PDFs online?
With most online mergers, "safe" means uploaded over an encrypted connection and deleted after some window — an hour, a day. Your file still left your device and sat on someone's server in between. FatafatPDF skips that step entirely: the merge runs with WebAssembly in your browser tab, so there's no upload to secure and nothing to delete later, because nothing was ever sent anywhere. Open DevTools → Network tab while merging and you'll see it yourself.
Can I merge PDFs on my phone — iPhone or Android?
Yes. The same browser-based tool works on mobile Safari and Chrome — tap to browse, pick your files from Files, iCloud Drive, or your device storage, reorder them, and merge. No app to install either way.
Can I merge a password-protected PDF?
Not directly — merging has to read every page, so an encrypted file needs to be unlocked first. Run it through our Unlock PDF tool (you'll need the password), then merge the unlocked copy along with the rest.