How to Merge PDFs on Mac and Windows (No Software to Install)
Both operating systems can combine PDFs, but neither does it well, and the methods differ enough that instructions for one are useless on the other. Here are the built-in routes and the one that behaves the same everywhere.
On macOS — Preview
- Open the first PDF in Preview.
- Show the thumbnail sidebar: View → Thumbnails.
- Open the other PDFs in Preview as well.
- Drag pages from the second document's sidebar into the first, at the position you want.
- Save with File → Export as PDF.
- Note the limitation: Preview merges pages, not files. Each source must be opened separately, and dragging thirty pages one at a time is tedious.
On Windows — no built-in way
Windows has no equivalent to Preview. Microsoft Print to PDF can only print one document at a time, so it cannot combine.
The usual advice is to install a third-party tool, which is what most people are trying to avoid.
Word can combine documents, but only if the PDFs convert cleanly to Word first — and that round trip damages the layout, especially on scanned files.
The approach that works on both
- Open the Merge PDF tool in any browser.
- Add all the files at once.
- Drag the cards into the order you want, and rotate anything sideways.
- Press Merge and download the single PDF.
- Nothing is installed, and the same steps apply on Mac, Windows, Linux and ChromeOS.
Why browsers are the better answer here
Merging is a well-defined operation: read the pages, write them into one document. Modern browsers can do it in memory with the same library a desktop application would use.
That means no installer, no admin rights on a work laptop, no "free" tool that watermarks the output until you subscribe, and no upload of a contract to somebody else's server.
Getting the order right
- Rename files with numeric prefixes (01-contract, 02-annex, 03-signature) before you start.
- If you cannot rename, sort by name inside the tool and check the list reading top to bottom.
- For interleaved pages from two documents, merge first and reorder the pages afterwards with Organize PDF.
- Check the first and last page of the result. Errors in order are most visible at the edges.
Privacy
Most online mergers upload every file. For a contract, an ID document or a bank statement, that means a copy exists on a server you do not control.
A browser-based merger reads the files and writes the result locally. Nothing is transmitted, and closing the tab leaves nothing behind.