PDF Merger

How to use PDF Merger

1. Drop in two or more PDFs, or click to pick them from your device.
2. Drag the files into the order you want them to appear.
3. Click Merge. The work happens locally, so large files depend on your machine, not a server queue.
4. Download the combined PDF.
5. Works offline once the page has loaded.
6. No file size cap other than the memory your browser tab can use, typically around 2 GB.
7. Encrypted PDFs need unlocking first.

What merging actually does to your file

A PDF is a container of page objects plus a cross-reference table that says where each object lives. Merging rebuilds that table and copies the page objects across, so text stays selectable and vector graphics stay sharp — nothing is re-rendered to an image. Fonts embedded in the source files are carried over and de-duplicated where two documents share the same face, which is why a merged file is usually smaller than the sum of its parts.

Order, rotation and page ranges

Files merge top to bottom in the list, and you can drag to reorder before merging. Pages keep the rotation stored in the source document, so a landscape scan stays landscape. If you only need part of a document, split it first and merge the piece — merging a 400-page file just to keep two pages wastes memory in the browser tab.

What it cannot do

Password-protected PDFs must be unlocked before they can be merged, because the page objects are encrypted until the password is supplied. Forms merge, but two documents with fields of the same name will collide and the second one wins. Digital signatures are invalidated by merging — that is the signature doing its job, since the document it signed no longer exists.