Merge PDF

Each PDF is opened in your browser and its page count read. The plan lists which pages of which file go into the output, in the order you arrange; the merged document is a new PDF into which those page objects are copied — content streams, fonts, images and page size exactly as they were. The reading and writing is done by pdf-lib, an open-source (MIT) PDF library that is downloaded to your browser only when you choose a file — the page itself stays small.

Page content, media box, crop box and rotation come across unchanged, so nothing is re-rendered or re-compressed. Each page's resources (fonts, images) are copied with it, which means a font shared by many pages of one source appears once in the output for those pages.

Bookmarks (the outline), form fields, named destinations and document-level metadata belong to the source document, not its pages, and are not merged; internal links may point nowhere in the new file. A password-protected PDF is refused rather than silently copied — remove the password first. Nothing leaves the browser: the file is read into memory on your device, rewritten there and offered back as a download; the same four anonymous usage counts as the rest of the site apply.