Converters
Merge PDF (Combine PDF Files)
Combine PDF files into one document in your browser. Reorder the pages before you merge — nothing is uploaded and no sign-up is asked for.
Drop PDFs here
Up to 20 PDFs, 100 MB each.
These files are read in this tab. They are never uploaded, and nothing is saved — not even on this device.
Combining a stack of PDFs is only half the job — the other half is landing them in the order a reader is actually meant to see them in, which is why the list you build here, not a settings panel, is the tool.
Combine PDF files in the order you choose
Add two or more PDFs and each one becomes a numbered row: a position badge, the file name, then a page count and size. That row order is the merge — the finished document runs through file one, file two, file three, exactly as the list reads when you press Merge PDFs. Nothing else about the output is configurable, because combining files is the entire job here, not converting or compressing them.
The same file can be added twice on purpose — a cover sheet used at the start and again as an appendix, say — and the tool doesn't flag it as a mistake. Two rows with different position numbers is a normal, deliberate use of this tool, not an error to correct.
Reorder PDF pages before you merge
Because a merged PDF's pages follow file order one-for-one — every page of file one, then every page of file two, and so on — arranging the files is how you set the page order of the document you'll download. There's no separate step for it and nothing to undo afterwards; the order in the list when you press Merge PDFs is the order the pages land in.
Three ways to set that order, and all three announce the same result so none of them is a second-class way to do it:
- Drag a row by its handle. The row lifts, an insertion line shows exactly where it will land, and the file drops into place on release. Nothing else in the list shifts until you let go.
- Move up / Move down, on every row. These are the long-distance way to reorder a list too tall to drag across in one gesture, and they're the only way to do it from a keyboard.
- Remove, on every row, if a file shouldn't be in the merge at all.
What this tool does not do is reorder, rotate or delete pages inside one file. If two files need pages interleaved with each other page-by-page — alternating sides of a double-sided scan, say — that's a different job this tool doesn't attempt; it moves whole files, and every page inside a file keeps its position relative to the others in that same file.
What happens to bookmarks and outlines
If your source files carry bookmarks — a PDF's outline pane, usually one entry per chapter or section — the merged file doesn't have any. Building a combined outline correctly means renumbering every page reference by however many pages came before it in the merge, deciding whether each file's chapters nest under a new top-level entry for that file, and doing it without knowing whether the source outline was accurate to begin with. Guessing at that is worse than an empty pane, so every page's content transfers intact and the navigation pane in the result is simply blank. If bookmarks matter for how the merged file will be read, add them afterwards in a PDF editor once the pages are in their final order.
What merging does to fillable form fields
Merging copies each page's visible content into the new document, but it doesn't carry the form-field definitions those pages depend on across with them — the merged PDF has no form fields at all, even when every source file was a fillable form. The pages look identical to the originals; there is simply nothing left on them to click into or type in.
That matters most for a form someone has already filled in. The values typed into a form live in those field definitions, not printed onto the page, so merging a filled-in form loses the entered data rather than keeping it under a different or duplicated name. If you need the entered values to survive, flatten the form in a PDF reader first — that bakes the typed text permanently into the page — and merge the flattened copy instead of the original fillable one.
Mixed page sizes and orientations in one file
Nothing here is resized, rotated or normalised to make files match. An A4 report merged with a Letter-sized annex keeps both sizes exactly as they arrived — the tool names it rather than leaving you to notice on page 9: "These files use different page sizes (A4 and Letter). Each page keeps its own size in the merged PDF." The same goes for orientation — a landscape scan dropped between portrait pages stays landscape. Scaling someone's document to match another changes what they gave you without being asked, so this tool states the mismatch instead of quietly fixing it.
Password-protected files, and what "not merged" means
A PDF that pdf-lib reports as encrypted is refused outright rather than guessed at:
"This PDF is password-protected, so its pages cannot be read. Open it in a PDF reader with the password, save an unlocked copy, and add that instead."
That's a statement of what's true about the file, not an error this tool made — merging is not the same job as unlocking, and offering to strip a password would be either guesswork or something closer to a lock-picking tool than a document assembler. A refused file never joins the ordered list at all, because a position number that contributes no pages would misstate what's actually in the output. It sits instead in a "Not merged" list of its own, named, with the reason beside it, and a Remove control if you want it gone rather than fixed.
The same "Not merged" list is where a file that isn't actually a PDF, one that's too large, or one that fails to open at all ends up — each named, each with the specific reason, never folded into a single vague "some files failed" line. Crucially, one bad file among several good ones doesn't stop the rest: merging four readable files while a fifth sits refused in its own list is the normal outcome, not a blocked one, and the result screen repeats exactly which file was left out and why.
Nothing survives after you leave
The files you add exist only in this browser tab's memory for as long as the tab is open. There's no upload, and there's also no local save on your own device — refreshing the page, closing the tab, or pressing Start over clears the list completely, including the merged result once you've downloaded it. That's deliberate: a merger that remembered your last file list between visits would be keeping a trace of documents it promised to leave no trace of.
Questions
- Can I merge PDF files free, with no sign-up or daily limit?
- Yes — there is no account, no sign-up, and no cap tied to a day or a session. The only limits are the ones printed on the drop zone: up to 20 PDFs in one merge and 100 MB per file, both there because the browser tab holding the files has to hold their bytes in memory. Neither limit resets on a timer, and neither is a paywall — there is nothing to pay for.
- How do I combine PDF files into one document?
- Drop or choose two or more PDFs, put them in the order you want the merged document to read in — drag a row by its handle, or use the Move up and Move down buttons — then press Merge PDFs. The result is one PDF whose pages run through file one, then file two, then file three, in whatever order the list showed when you pressed the button. There is nothing to configure beyond that order: no compression setting, no output format choice, because the whole job is combining, not converting.
- Does merging PDFs without uploading actually mean nothing leaves my device?
- Yes. The files are read into this tab's memory and merged there with a PDF library running in your browser — there is no server call in this tool at all, so there is nothing for a file to be uploaded to even if the tool wanted to send one. That's not a policy choice that could quietly change; the code that runs this page is not permitted to make network requests, so the files physically cannot leave the tab they were dropped into.
- Can I join PDF files offline, without an internet connection?
- Once the page and its PDF engine have loaded, yes — the actual merge runs entirely in your browser and touches the network for nothing, so a dropped connection partway through a merge does not interrupt it. The one thing that does need a connection is the very first load of the page (and, the first time you add a file in a session, a one-time download of the PDF engine itself). After that, adding more files and merging them again works with no connection at all.
- Do bookmarks and outlines survive when you merge PDFs?
- No — the merged file has no bookmarks or outline entries at all, even if every source file had its own. Combining outlines correctly would mean deciding how each file's chapter list nests under a heading for that file, choosing where page numbers should point once they've shifted by however many pages came before them, and doing that for outlines that may already be broken in the source file. This tool doesn't attempt any of that guessing — every page transfers with its content intact, and the navigation pane in the merged PDF is simply empty.
- What happens to form fields when you merge PDF forms?
- They're dropped, not carried over — the merged PDF has no form fields at all, even when every source file had its own. Merging copies each page's visible content into the new document, but it doesn't copy the underlying form-field definitions those pages pointed to, so a merged form comes out looking identical to the original but with nothing left to type into. That matters most for a form somebody has already filled in: the entered values live in those dropped fields, not printed on the page, so merging a filled form loses the data rather than keeping it in a differently-named field. If you need the entered values preserved, flatten the form in a PDF reader first — that bakes the typed text into the page itself — and merge the flattened copy instead.
- Can I merge PDFs that have different page sizes, like A4 and Letter?
- Yes, and nothing is resized to make them match — each page keeps the exact size it arrived with. When the files you've added use more than one page size, the tool tells you so directly ("These files use different page sizes (A4 and Letter). Each page keeps its own size in the merged PDF"), both while you're still arranging the list and again on the result once it's built, so it's stated rather than something you discover by opening the file afterwards.
- Why does it say my PDF is password-protected when I try to merge it?
- Because it is, and an encrypted PDF cannot be read at all — not by this tool, not by any tool — until it's unlocked with the password. The message is exact: "This PDF is password-protected, so its pages cannot be read. Open it in a PDF reader with the password, save an unlocked copy, and add that instead." This tool does not attempt to guess, crack or strip a password; open the file in a PDF reader, save an unlocked copy from there, and add that copy instead. If it was one file out of several, the rest merge normally — a password-protected file is left out and named, not blocked for everyone else in the list.