This tool combines two or more PDF files into a single document, in whatever order you arrange them. It's the fix for the common mess of having a contract, an invoice, and a set of scanned signatures as three separate files when you need to send one.
The merge happens entirely on your device using pdf-lib, a PDF-manipulation library that runs in the browser, your files are read locally, stitched together in memory, and the combined PDF is handed back to you as a download. None of it touches a server, so there's no upload wait, no file left sitting on someone else's storage, and it works the same on a phone with one bar of signal as it does on fiber.
You can drag files into any order before merging, and the page count of each source document carries through unchanged, nothing gets rasterized or recompressed, so text stays selectable and image quality stays exactly as it was in the originals. The only real ceiling is your device's own memory when combining a very large number of very large files, which is rarely a practical issue for normal use.
This is one of the most-used tools here for a reason: assembling a single PDF from parts that arrived separately is one of the most common everyday document tasks there is, a signed page that needs to go back into the main contract, a cover letter that needs to sit in front of a resume, scanned receipts that need to become one expense report. Since merging on most sites means uploading every file first and waiting, doing it on-device instead is noticeably faster in practice, especially when merging several large scanned PDFs on a phone connection.
How to Merge PDF
- Add two or more PDF files: drag them in or select from your device.
- Drag the file thumbnails to set the order you want them merged in.
- Tap "Merge PDFs."
- Download the single combined PDF file.
Frequently asked questions
Is there a limit on how many PDFs I can merge?
No hard limit, you can merge as many files as your device can comfortably hold in memory at once.
Do my files get uploaded to merge them?
No. Merging happens entirely in your browser using pdf-lib; your files never leave your device.
Can I merge PDFs on my phone?
Yes, the tool is mobile-first and works the same on a phone browser as on a desktop.
Will merging affect the quality of my pages?
No. Pages are combined as-is, not re-rendered or recompressed, so text and images stay exactly as sharp as the originals.
Do I need to create an account?
No account, no signup, just open the tool and use it.
Related tools
- Split PDF: Split a PDF into separate files by page range.
- Reorder Pages: Drag and drop page thumbnails to change their order.
- Compress PDF: Shrink file size with five presets, or target an exact size.
- Extract Pages: Pull specific pages out of a PDF into a new file.