Merge 2 PDFs

How to merge two PDF files in the right order

The tool joins files in the order they appear in its list, and the list follows the order you added them. That is rarely the order you want, because file pickers sort alphabetically and documents do not. A cover letter named "letter.pdf" ends up after a CV named "cv.pdf" unless you move it.

Move them before you merge. The order shown in the list is the order in the output, with no hidden rules and no sorting applied behind your back. Check it once and the rest is automatic: 2 files in, 1 file out, in the order you set.

Step 1: Add both files

Open the merge tool and drop both PDFs in. The list shows them in the order they arrived, which is usually alphabetical because that is how file pickers sort.

Step 2: Check and fix the order

Look at the list. If the file you want first is second, use the arrow buttons to move it up. The order in the list is exactly the order in the output, with no surprises.

Step 3: Merge and download

Press merge. The tool joins the two files, re-opens the result, and compares page count, page order, page sizes, and selectable text against both sources before the download appears. A result that fails verification is not offered for download.

What the verification check actually does

After the merge, the output is re-opened and read back. Page count and page order are compared against the two sources, each page keeps the size it had, and the selectable text on each page is compared with its source. A result that fails verification is not offered for download.

That matters more than it sounds. A merge that silently drops an annotation layer or a form field produces a document that opens cleanly and is missing something you needed. Reading it back is the only way to know, and pdfviz does that on every run, in the browser, without sending anything anywhere.

Real-world use cases for merging two PDFs

Job applications are the most common reason people merge two files. A cover letter and a CV go into one document so the recruiter sees them in the right order and in one attachment. The order matters: the cover letter goes first, and file pickers often put it second because of alphabetical sorting.

Contract signing is another case. A signed signature page and the main contract body need to be one file before they go to the counterparty. Merging them in the browser means the signed document never leaves your machine until you choose to send it.

Invoice and receipt bundles, grant application attachments, and visa supporting documents all run into the same need: two PDFs that belong together as one file. The merge tool handles all of them, and the verification step means the output is checked before you download it.

When two files is not the right shape

If you have five or six files, use the multiple file page rather than merging in pairs. Doing it in pairs means a pass per extra file, a fresh chance to get the order wrong each time, and no benefit. One pass with the whole set gives you one list to check and one verified output.

If what you actually want is to interleave pages, or to put one document inside another rather than after it, merge first and then reorder with the organize pages tool. The two file merge guide walks through both cases, including what to do when the files came from different scanners.