How to merge PDF files into one document

Before you merge: get the order right

Most merge tools, including ours, combine files in the order you add them. That sounds obvious, but the order you select files in a folder is not always the order you want them to appear. Think about the final document from the reader’s point of view before you start.

A few useful conventions: cover page first, then the main body, then appendices, then supporting evidence. For receipts or invoices, chronological order is almost always the clearest.

How to merge PDFs in the browser

Using the free web tool, you can combine several files in a few seconds:

• Open the Merge PDFs tool.
• Select two or more PDF files — you can add more than one at a time.
• Arrange them in the order you want the pages to appear.
• Run the merge and download the single combined PDF.
• Open the result and check the first and last pages of each source document.

Clean up pages before or after merging

Merging is often only half the job. If one of your source files contains pages you do not want in the final document, deal with that first so you do not have to untangle it later.

• Use Extract Pages to pull just the page ranges you need out of a longer file.
• Use Split PDF to break a large file into separate documents before recombining them.
• Use Rotate PDF to fix any sideways or upside-down scans so every page faces the same way.

Common mistakes to avoid

A merged PDF is easy to get almost right and surprisingly easy to get subtly wrong. Watch for these:

• Duplicated pages, especially when a cover sheet appears in two source files.
• Mixed orientation, where scanned pages sit sideways next to digital ones.
• Wildly different margins, which is normal when you combine scans with exported documents but worth a quick look.
• Password-protected source files — unlock them first, since a locked PDF cannot be merged cleanly.

When one document is not the right answer

Sometimes merging makes a file harder to use rather than easier. If the combined document would run to hundreds of pages, or if different sections will be updated at different times, it is often better to keep them separate and share a folder or a table of contents instead.

Merging works best when the pieces genuinely belong together as one record: a single application, one contract, one expense claim.