Documents & Files / PDF Tools

PDF Merger & Splitter

PDF Merger & Splitter joins multiple PDF files into a single document, or cuts one PDF into separate files by page range or a fixed number of pages per chunk. Every page is copied locally in your browser, so no file is ever uploaded to a server.

How to use

1
Add your PDF files
Drag one or more PDFs onto the drop zone, or click it to open your file picker. Each file is read immediately and its page count is detected, so anything that is not a real PDF, or that turns out to be password-protected, is flagged in the list before you try to process it.
2
Set the merge order
In merge mode the order of the list is the order of the finished document. Drag any row by its handle, or use the up and down arrow buttons, to move a file earlier or later, and the position number on the left updates the moment you drop it somewhere new.
3
Choose merge or split
Switch between Merge PDFs, which combines everything currently in the list into one file, and Split PDF, which divides a single document. In split mode only the first valid file in the list is used as the source, so remove any file you do not want divided into separate pieces.
4
Define the split points
Pick By page ranges and enter a specification such as 1-3, 5, 8-10, where each comma-separated entry becomes a separate PDF. Or pick Every N pages to cut the document into equal chunks of N pages, with the final chunk holding whatever pages are left over.
5
Process and download
Press the action button and the work happens locally in your browser. A merge downloads as a single PDF; a split downloads one ZIP archive holding a PDF for every range, so you collect the whole set in a single step. Large files can take a few seconds while the tab works.

Key facts

PDF standardThe PDF format was released by Adobe in 1993 and became the ISO 32000 international standard in 2008; ISO 32000-2 is maintained today as PDF 2.0.Source:ISO 32000-1:2008 / ISO 32000-2:2020
Where the work happensMerging and splitting run entirely in the browser through pdf-lib, so no file is transmitted to a server and no copy is stored.Source:This tool
Page range syntaxA comma-separated specification such as 1-3, 5, 8-10 yields one PDF per entry, bundled into a single ZIP archive.Source:This tool

Frequently asked questions

Are my PDF files uploaded to a server?

No. Both merging and splitting happen inside this page. When you pick a file the browser reads it into memory through the File API, pdf-lib copies the pages you asked for, and the result is packaged into a Blob that you download straight from memory. The file is never posted anywhere, and there is no server component that could receive it. That matters more for PDFs than for most file types, because contracts, invoices, medical records and signed forms are exactly the documents people consolidate and split. You can confirm the claim yourself: open your browser developer tools, switch to the Network panel, then merge or split a file and watch the request list. The only entry that appears is the download of the finished result.

Is there a file size limit?

This tool imposes no limit of its own, but two practical ceilings apply. The first is device memory: the pages you keep are held as decoded objects, so a few hundred megabytes of input can exhaust a tab on a laptop that is already busy. The second is patience — pdf-lib is written in pure JavaScript, so a very large document may take several seconds to copy and the tab will look frozen while it works. Documents under roughly 100 MB process comfortably on a modern machine, and the tool never refuses a file merely for being large. If a merge fails on a very big input, close other tabs and try again. Splitting a single document is the cheaper operation, because only the pages belonging to each chunk are ever copied into a new file.

Can this tool open password-protected or encrypted PDFs?

Not if the document is actually encrypted. pdf-lib, the library that performs the copying, can load a PDF only when it is able to read the file structure, and an encrypted file refuses that read — so the tool reports that the file could not be read as a PDF rather than quietly producing a damaged result. You will need to open the document once in a PDF reader that accepts the password, then save or export a decrypted copy before merging it here. Note the distinction between the two kinds of protection: a file carrying only an owner password that restricts editing is usually still readable, while one carrying a user password that blocks opening is not. This tool does not attempt to break either, and no password is ever requested or transmitted.

Does merging or splitting change the pages or reduce quality?

No. pdf-lib works at the level of PDF objects rather than pixels: it copies the existing page content streams and the resources they reference into a new document instead of re-rendering anything. Text stays selectable, vector artwork stays vector, embedded fonts and images are carried across unchanged, and the native resolution of any scanned page is preserved exactly. What can change is the file size, in either direction. Merging several files usually shrinks the total, because shared resources such as fonts are not duplicated once per source document. A merged file can also grow larger than the sum of its parts when the sources embed duplicate copies of the same font under different internal names, since each copy is retained. Neither outcome affects how the pages look.

What page range syntax does the splitter accept?

The page range field takes a comma-separated list, and each entry becomes its own PDF inside the resulting ZIP archive. A single number such as 5 selects one page; a range such as 1-3 selects pages one through three; and a mixed list such as 1-3, 5, 8-10 produces three separate documents in that order. Pages are numbered from one, not from zero, and the tool validates the request against the real page count, so asking for page 12 of a ten-page document reports the actual total instead of quietly returning an empty file. If you would rather not think in ranges at all, switch to Every N pages and the document is chopped into equal chunks of that size, with a shorter final chunk whenever the page total does not divide evenly.

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