Merge PDF
Combine several PDFs into one, in the order you choose.
This tool runs entirely in your browser. Your file is never uploaded, and you can verify that in your browser's network tab. Verify it yourself: open your browser's network tab and watch. You will see one small request asking whether you have tasks left - a tool name and a hash, never the file.
What this does
Merging turns several PDFs into one document. The pages are copied in the order you set, and everything on them - text, images, links, form fields - is carried across untouched. Nothing is re-encoded, so the result looks exactly like the originals and there is no loss in quality.
Reach for it when a set of files needs to travel as one: chapters of a report, a scanned contract that arrived as separate pages, an application where the form and the supporting documents must be uploaded in a single attachment, or the front and back of a document your scanner saved separately.
How it works
- Drop your PDFs onto this page, or use the file picker. You can add more at any time.
- Drag the files into the order you want, or sort them by name or size. The number on each row is the position it will take in the finished document.
- Turn on a blank page between files if the result will be printed double-sided, so each document starts on a fresh sheet.
- Press Merge. Progress shows the page being copied, and Cancel stops it immediately.
- The download starts on its own. There is no waiting screen and no second click.
Order is the part people get wrong most often, so it is the part this tool makes most visible. Sorting by name uses natural number ordering, which means scan-2 comes before scan-10 rather than after it - the opposite of what plain alphabetical sorting does, and the reason merged scans so often arrive shuffled elsewhere.
Bookmarks are rebuilt rather than dropped. Most merge tools discard the outline because copying pages does not copy the tree that points at them; here the outline of every source is read, its destinations are re-pointed at their new page positions, and the trees are joined under one root. If a bookmark pointed at a page that was not included, its children are promoted rather than lost with it.
The file never leaves your device. The merging happens in a Web Worker inside your browser using pdf-lib, so no page of either document is ever handed to a server. You can confirm this yourself: open your browser's network tab, merge a file, and watch what goes out - one small request asking whether you have tasks left, carrying a tool name and a hash, and never the file.
There is no page limit, no daily quota and no wait between jobs. The only real constraint is your device's memory, and if a file is large enough to be a risk we say so rather than silently refusing.
Questions people ask
- How do I control the order of the pages?
- The list under the drop zone is the order of the finished document, top to bottom. Drag a row to move it, or use the arrow buttons if you are working with a keyboard. You can also sort automatically by file name or size. Sorting by name is natural-numeric, so page-2 comes before page-10.
- Is there a limit on how many files or pages I can merge?
- You can merge up to 50 files at once, and there is no page limit at all. That ceiling exists because a list longer than 50 stops being checkable by eye, not because of a paywall - merging in two batches works exactly as well. There is no daily quota and no cooldown between jobs.
- Will my bookmarks and table of contents survive?
- Yes, if you leave Keep bookmarks on. The outline of every file is read and rebuilt so each entry still points at the right page in the merged document. Bookmarks whose target page was excluded are dropped, but anything nested under them is kept and moved up a level.
- Are my files uploaded to a server?
- No. The merge runs entirely in your browser using WebAssembly, and no part of the file is transmitted. This is verifiable rather than a promise: open your browser's developer tools, switch to the network tab, and merge a document. You will see one small request asking whether you have tasks left - a tool name and a hash of the bytes, never the file itself.
- Why does my password-protected file fail?
- An encrypted PDF cannot be read without its password, so its pages cannot be copied. Remove the protection first with Unlock PDF, then merge. If the file opens without a password but still refuses to merge, it carries owner restrictions that Unlock PDF can also remove.
- Does merging reduce quality or make the file bigger?
- Quality is untouched - pages are copied as they are, with no re-encoding of text or images. Size is usually a little less than the sum of the parts, because shared resources such as an identical letterhead or an embedded font are stored once rather than repeated. If you need it smaller still, run Compress PDF afterwards.