Merge PDF files — free, private, in your browser

Merging PDFs is one of those everyday tasks that usually means uploading sensitive documents to a stranger’s server. This tool does it differently: every file you add is combined directly inside your browser using WebAssembly, so nothing ever leaves your computer.

There are no page limits, no watermarks and no sign-up. Add as many PDFs as you like, drag them into the order you want, and download a single, clean document.

How it works

When you add PDFs, the tool reads each file directly from your device into memory and hands it to pdf-lib, a PDF engine compiled to WebAssembly that runs inside the browser tab. No file is ever sent over the network, so the documents stay on your machine from start to finish.

Merging is done by copying pages from each source document into a new, empty PDF in the order you choose. The copy is lossless: text remains real selectable text, fonts and images are preserved, and vector graphics stay sharp because nothing is re-rendered or re-compressed. When you click download, the finished file is generated locally and saved straight to your device.

When to use it

Combining PDFs is handy whenever separate documents really belong together as one file. Stitch scanned pages, a cover letter, and a CV into a single application; bundle invoices and receipts for an expense report; assemble chapters or handouts into one reader; or join signed contract pages back into a complete agreement before archiving.

Because the merge happens entirely on your device, it is especially well suited to confidential material such as legal paperwork, medical records, financial statements, and HR documents. There is no upload step to worry about, so you can combine sensitive files without sending them to a third party.

Tips

Set the page order before you merge by dragging the files into position; the merged document follows the top-to-bottom order shown in the list. Rename your files beforehand if order matters, since a clear naming scheme makes the sequence easy to confirm at a glance.

If you only need a few pages from a large PDF, split or extract those pages first and then merge, so the final file stays lean. Working with very large or image-heavy documents uses more memory, so close unneeded browser tabs if a big merge feels slow. Finally, always open the downloaded file to confirm the page order looks right before you send it on.

How to use Merge PDF

1. Add your PDF files by dropping them onto the box above or clicking to browse.
2. Drag the files (or use the arrows) to arrange them in the order you want.
3. Click “Merge PDFs” — the documents are combined instantly in your browser.
4. Download your merged PDF. Nothing was ever uploaded.

Frequently asked questions

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