BuzzKit
Merge PDF
Combine two or more PDF files, in order, into a single document.
Documents merge in the order the files were selected.
Pages keep their original formatting — merging only reorders documents, it doesn't re-render them.
What this tool is for
Documents rarely arrive as one tidy file. A signed contract might exist as a cover page, a scanned signature page, and an appendix, all separate. An application might need a resume, a cover letter, and certificates combined into a single upload. A scanner might save each page as its own PDF. This tool combines any number of PDF files into one document, in the order you choose, without needing desktop PDF software or uploading anything to a third-party service first.
It's aimed at anyone assembling a document from parts: combining scanned pages into one file, merging a cover letter with a resume for a single upload, or joining chapters, invoices, or reports that were created or received separately. If your goal is the opposite — pulling specific pages out of one larger PDF — use Split PDF instead.
How the merge PDF tool works
This tool uses pdf-lib, a JavaScript library for reading and writing PDF documents, and specifically its copyPages() method. Rather than converting each page to an image and reassembling them (which would degrade text and increase file size), copyPages() copies the actual page objects — including their embedded fonts, vector graphics, and selectable text — directly into a new document. This is why merged PDFs keep their original formatting exactly: nothing is re-rendered, only reassembled.
The practical trade-off is that this only works cleanly between valid PDF documents. If a source file is a scanned image saved as a PDF, its "pages" are just embedded images with no underlying text, and merging preserves that exactly as it was, images and all, but a scanned page won't gain selectable text just by being merged — that would require optical character recognition, which this tool doesn't perform.
Common situations this solves
- Combining a cover letter and resume into a single file before submitting a job application.
- Merging scanned pages from a scanner or scanning app that saved each page separately.
- Assembling a contract from a main document, a signature page, and supporting exhibits.
- Combining multiple invoices or reports into one file for a single email attachment or archive.
Limitations, honestly
There's no hard page or file-count limit, but very large combined documents — many files or hundreds of pages — take longer to process and use more of your browser tab's memory, since the whole operation happens on your device rather than a server. Page order follows the order you select files in, so double-check the sequence before merging if it matters. If a source PDF is password-protected, it needs to be unlocked before merging, since this tool doesn't handle encrypted PDFs.
Frequently asked questions
Will formatting, fonts, or text selection change?
No. Pages are copied directly with copyPages(), not re-rendered, so fonts, vector graphics, and selectable text all carry over exactly as they were in the source file.
Is there a page or file limit?
No hard limit, though very large combined documents take longer to process and use more browser memory.
Can I remove a page before merging?
Use Split PDF first to isolate only the pages you want, then merge the results.
Can I merge password-protected PDFs?
Not directly — an encrypted PDF needs to be unlocked first, since this tool works with unprotected documents.
Does merging change the file size much?
The result is roughly the sum of the source files' sizes, since pages are copied rather than recompressed. Use Compress PDF afterward if the combined file is too large.
Will merged scanned pages become searchable text?
No. Merging preserves pages exactly as they are — a scanned page without underlying text stays that way, since this tool doesn't perform text recognition.
Does the order I select files in matter?
Yes — pages appear in the merged document in the same order you added the source files.
Does this upload my documents anywhere?
No. Merging happens locally in your browser using pdf-lib — files are never sent to a server.