Merge PDF
Add as many as you need. They merge in the order shown.
Add at least two PDFs
Files are read in this page and never uploaded. Merging happens entirely in your browser.
Several PDFs are joined into a single document, in whatever order you arrange them. Every file is read and written in your browser. Nothing is uploaded, which is the difference that matters when the documents are contracts, invoices or medical records.
How it works
Each source document is parsed, its pages are copied into a new document, and the result is serialised back out. Copying a page brings its content stream and the resources it references (fonts, images, colour spaces) so pages keep their appearance rather than being re-rendered.
- Text stays selectable and searchable, because the page content is copied rather than flattened to an image.
- Pages keep their individual sizes, so merging A4 and Letter documents produces a file with both. That is valid, and some printers will complain about it.
- Files merge in the order listed, and the arrows move them. Nothing is sorted automatically, because the right order is rarely alphabetical.
- Bookmarks, form fields and annotations are not carried across, page copying moves the page, not the document-level structures around it.
The merged file is roughly the sum of its inputs. There is no cross-file deduplication here, so if the same font is embedded in five documents it will be embedded five times in the result.
Examples
Three reports into one
Files
12, 8 and 20 pages
Result
One 40-page PDF
Pages appear in file order, and the order shown on the page is exactly the order used.
Mixed page sizes
Files
One A4, one Letter
Result
A valid PDF with both sizes
PDF allows per-page dimensions. It prints correctly in most cases and occasionally confuses a printer's tray selection.
A file that will not open
File
A password-protected PDF
Result
Rejected with a reason
Encrypted documents cannot be read without the password, which this cannot ask for. Remove the password in the application that made it.
Frequently asked questions
Do the PDFs I merge leave my machine?
No. Each PDF is read with the browser file API and the merge happens in this page. No network request carries the documents, which matters because the files people merge are so often contracts, invoices and scanned records.
Is there a limit on file size or count?
Files above 100 MB each are refused, since a browser tab will not handle one reliably, and there is no count limit, but every file is held in memory at once. A few hundred megabytes total is where a tab starts to struggle.
Does merging reduce quality?
No. Pages are copied intact, not re-rendered, so text stays selectable and images keep their original resolution. The merged file is roughly the sum of the inputs, since there is no cross-file deduplication of shared fonts.
What happens to bookmarks and form fields?
They are lost. Copying a page brings its visual content and the resources it needs, but bookmarks, form field definitions and annotations live at the document level and do not travel with individual pages. The merged file has the right pages and none of that structure.
Why was my password-protected file rejected?
Because it is encrypted and the content cannot be read without the password. There is no way to prompt for one here. Open the file in a PDF reader, save an unprotected copy, and merge that.