Select the PDFs to merge: they are combined into a single document, in the order they appear in the list.
Merging PDFs almost always happens for the same reason: sending one bundle instead of six attachments. A contract plus its annexes, an invoice plus its receipt, the chapters of a thesis scanned separately. The recipient opens a single file and has nothing to put back in order.
The tool reads the documents you select, copies all their pages and writes them into a new PDF, keeping the order of the list. The pages are not recompressed or regenerated: text, images and fonts stay identical to the originals, and the final file weighs as much as the sum of its parts.
If the order is not the one you want, remove the files with the cross and select them again in the right sequence.
How many PDFs can I merge at once?
The site sets no limit. The constraint is your browser's memory: on a recent computer dozens of documents are handled without trouble, on a phone it is better to stick to a few files at a time.
Does merging reduce the quality of the document?
No. The pages are copied as they are, without recompression. The result looks identical to the originals and the text stays selectable.
Does it work with password-protected PDFs?
No. An encrypted PDF cannot be opened without its password, and PizzaPDF does not bypass any protection. Remove the password from the original file and try again.