Merge PDF Files

The merged file follows the list shown under the picker, top to bottom. Every time you choose more files, they're added to the bottom. The × beside a name removes it. There's no dragging to reorder, so if a file lands in the wrong place, remove the files below it and add them again in the order you want.

When you select several files in one go, your operating system's dialog decides the order they arrive in. The safest way to control the order is to add files one at a time, or to name them 01-cover.pdf, 02-report.pdf and so on so they sort correctly.

The tool builds a brand-new PDF and copies each page into it, together with everything that page uses: text, fonts, images, and annotations such as comments and web links. Each page keeps its own size and rotation, so a landscape A4 page and a portrait Letter page sit side by side without being resized.

Things that belong to a document as a whole, rather than to a page, are not copied:

• Bookmarks (the outline in your viewer's sidebar) are lost.
• Form fields lose their link to the document's form, so fillable fields may stop working.
• Title and author are not kept; the new file lists pdf-lib as its producer.

The download is called merged.pdf.

The PDF library used here can't decrypt files. The tool opens encrypted PDFs without decrypting them, and that includes files that open without a password but block printing or editing. The pages of such a file can come out blank or garbled in the merged document, with no error shown. Remove the protection first, using the password in software you trust, and merge the unprotected copy.

The code sets no limit on the number of files or pages. Everything is read into your browser's memory and combined on your device, which also means the files aren't uploaded. Large scanned documents may take longer on a phone than on a laptop.