How to use the merge PDF files
- 1Press Choose PDFs (or drag files onto the box) and add two or more PDFs. You can add more later.
- 2Put the files in order with the up and down arrow buttons on each row, or drag a row. The file at the top comes first.
- 3To take only some pages from a file, type them in the box on its row, for example
1-3, 5. Leave it empty to include every page. - 4Edit Output file name if you like, then press Merge PDFs and Download.
Example
report.pdf (12 pages), pages box: 1-3, 5 appendix.pdf (4 pages), pages box empty
merged.pdf with 8 pages: report pages 1, 2, 3 and 5, then appendix pages 1–4
Pages keep their size and orientation, so a landscape page stays landscape in the merged file.
Ordering files and pages
Files are merged from top to bottom. Each row has Move up and Move down buttons (the arrows), so you can reorder with a keyboard or on a phone; dragging a row works too on a computer. Every move is announced to screen readers.
The pages box on each row decides which pages of that file are used and in what order. It accepts single pages and ranges separated by commas: 1-3, 5 takes four pages, 8- runs from page 8 to the end, and 5-1 takes pages 5 down to 1 in reverse. To reorder pages inside one file, add the file twice with different ranges, or split it first with split PDF.
Large files and page limits
There is no fixed page limit. Each file can be up to 100 MB, and the practical limit is your device's memory: the merged PDF is built in the browser tab, so the files you add plus the result must fit in memory at the same time. Several hundred pages are normally fine on a laptop. If a phone struggles, merge in two rounds.
Merging copies pages as they are and doesn't re-compress them, so the result is roughly the sum of the inputs. To shrink it afterwards, use compress PDF.
Password-protected PDFs
A PDF that needs a password to open, or that is encrypted to prevent changes, is rejected with a message naming the file. The tool can't remove encryption. Open the file in a PDF viewer with its password and save or print a copy without protection (for example Print → Save as PDF), then add that copy.
Files that aren't PDFs, are empty, or are damaged are also rejected individually, so one bad file doesn't stop the others from being added.
How in-browser processing works
The merge uses pdf-lib, a JavaScript PDF library that loads into this page the first time you press Merge PDFs. It reads each file from your device, copies the selected pages into a new document and saves it. Nothing is sent to a server, so the speed depends on your device rather than your upload connection, and the tool keeps working if you go offline after the page has loaded.
Your original files are never changed. The download stays available until you change the file list.
Are my files uploaded?
This tool runs entirely in your browser. Your PDF files are not uploaded to our servers.