Merge PDF files

What merging does

Merging copies the pages of several PDFs into one new document, in the order you specify. The original files are untouched, the pages are not re-rendered or recompressed, and text remains selectable and searchable exactly as it was. Bookmarks and form fields from the source files are not carried over, which rarely matters for the everyday cases: combining a cover letter with a CV, stitching together chapters of a report, gathering signed pages from several people, or assembling supporting documents for an application into a single upload.

Controlling the order

Files are merged in the order they appear in the list. Drop them in the order you want, or name them with a numeric prefix so they sort correctly. Check the list before running: the most common merge mistake is having the appendix land before the introduction.

Mixed page sizes and orientations

PDFs with different page sizes merge without any problem; each page keeps its own size, so an A4 report followed by a landscape A3 drawing produces a document with both. Viewers handle this fine. If you need uniform pages for printing, print to PDF from your viewer afterwards with "fit to page" enabled.

Security and locked PDFs

A PDF that is encrypted with an open password cannot be merged until it is unlocked, because the pages cannot be read. Open it in a viewer, enter the password and save an unlocked copy first. PDFs with only an owner password (printing or editing restrictions) usually merge normally.

File size after merging

The merged file is approximately the sum of the source files. Shared resources such as fonts are not deduplicated across sources, so it can be slightly larger. If the result needs to be smaller, run it through the PDF compressor, keeping in mind that compression works best on scan-heavy documents and does little for text-only PDFs, which are already small.

Practical examples

• Combine a signed signature page returned by email with the unsigned body of the contract.
• Assemble an application pack: form, ID, proof of address, bank statement, all as one PDF.
• Join monthly statements into a single annual file for the accountant.
• Merge lecture notes downloaded as separate PDFs into one document for reading offline.
• Collate a set of invoices into one file for a purchase order.

Because merging happens entirely in your browser, confidential documents such as contracts, medical records and financial statements are never uploaded anywhere.