Merge PDF Files, in Any Order

Add two or more PDFs, then drag them into the order you want or move them with the up and down buttons. Every row shows the page count of its file, and the summary shows the total number of pages the merged document will have. A text field on each row lets you take only some pages from that file, for example 1-3,7 or 5-, and the total updates as you type.

The merged PDF is created in your browser with pdf-lib and offered for download under the file name you choose. Files are opened one at a time while merging, so memory use is closer to the size of the result than to the size of every input added together.

Each file is checked as soon as it is added. A file that is not really a PDF, is damaged or truncated, or is empty gets a message on its own row, and it is skipped when you merge. The other files are not affected. A page range that does not fit the file, such as 12 pages requested from a 10-page PDF, is flagged under the field, and merging waits until it is fixed.

Encrypted PDFs are a limit of the library: files protected with a password or with certain permission settings cannot be edited here, and the row says so. Open the file in a viewer that can print to PDF, save an unprotected copy and add that instead.

Pages are copied with their content, fonts, images and rotation. What is not carried over is the document-level structure: bookmarks (outlines), interactive form fields, document title and author, and tagged-PDF accessibility structure are not copied into the merged file, and links that jump to other pages in the same original document may not work. If you need those, use a full PDF editor.

You can merge up to 30 files, each up to 100 MB and 300 MB in total. Very large merges can exhaust the memory of phones, so merge in stages if needed. The tool never changes your original files. If the result is larger than you need, run it through a PDF optimiser afterwards, since merging does not recompress images.