How to Merge PDF Files

Learn how to combine multiple PDF documents, arrange pages, check the output and avoid common ordering mistakes.

Merging PDFs combines separate files into one document. It can be useful for applications, reports, invoices, project packages and scanned paperwork where a single file is easier to upload or share.

Arrange the source files

Before merging, decide the desired order. A simple approach is to name files with numbers such as 01, 02 and 03, or use the tool’s displayed file order when selecting documents.

Check the merged document

Open the resulting PDF and confirm that every source document is present. Check page order, page orientation, blank pages, links and important visual elements. If the final document will be submitted, also check the file size against the submission limit.

Keep your originals

Merging creates a new file; it should not replace your source documents. Keeping the originals makes it possible to rebuild the package later if a page needs to be corrected or removed.

Check the result before using it

A calculator is most useful when the inputs match the question you are trying to answer. Check units, dates, rates, periods and rounding before copying a result into a document or decision. For financial calculations, compare the estimate with the actual terms supplied by a lender, employer, bank or other provider. For documents and images, keep the original file and inspect the processed copy before sharing it.

Use the related UniConvertHub tool

The interactive How to Merge PDF Files tool is designed to make the calculation or file task quick to test in a browser. You can also browse the full guide library for related explanations.