How to use the merge pdf
- Drop two or more PDF files onto the drop zone, or click it to choose files.
- Put the files in order by dragging the handle, or with the up and down buttons.
- Optionally type page ranges for any file, for example 1-3, 5 or 8- to take page 8 to the end. Leave it empty to include every page.
- Click Merge and download the combined PDF.
Worked example
A 3-page contract plus page 2 of a 2-page annex
Add contract.pdf (3 pages) and annex.pdf (2 pages), type 2 as the range for the annex and merge. The result has 4 pages: contract pages 1 to 3, then annex page 2. Typing 3,1 for the contract instead would put its page 3 before page 1.
How it works
Each file is opened with the pdf-lib library. The pages you selected are copied into a new document with copyPages, which carries over page content, fonts, images and annotations without re-compressing them. The new document is saved with compressed object streams.
Assumptions
- Page ranges are 1-based and follow the order you type, so repeats and reversed orders are allowed.
- Files are merged in the order shown in the list.
Frequently asked questions
Are my files uploaded?
No. Your PDF is processed in your browser on your own device and is never sent to our server. You can disconnect from the internet after the page loads and the tool still works.
Is there a limit on the number of files?
You can add up to 40 PDFs, each up to 100 MB and 400 MB in total. In practice the limit is your device memory, since everything happens in the browser.
Are bookmarks and form fields kept?
Page content, annotations and web links are kept. Bookmarks (the outline), fillable form behaviour and document-level attachments are not carried over into the merged file.
Can I use a password protected PDF?
Not for editing. Encrypted or permission-restricted PDFs are refused, because editing them without decrypting would create a broken file or bypass restrictions set by the author. If you are allowed to, remove the protection in the software that created it first.
Limitations
- Files up to 100 MB are accepted, but very large or complex PDFs depend on your device memory and can be slow on phones.
- Bookmarks, interactive form fields and embedded file attachments are not preserved.
- Encrypted or permission-restricted PDFs cannot be merged.