How to Merge PDF Files on Windows, Mac, iPhone and Android
Every way to combine PDF files into one, on any device, with or without extra software. Plus the mistakes that make merged PDFs huge or out of order.
Merging PDFs sounds like something every computer should do out of the box. Surprisingly, it depends a lot on which device you are holding. Some systems have a hidden built-in way, some need an app, and some force you into a paid subscription for what is essentially copying pages from one file to another.
We built a merge tool ourselves, so we have tested most of the alternatives. Here is what actually works on each platform, and what we recommend.
The quickest way on any device: in the browser
If you just want one file and do not care how, open Merge PDF, choose your files, put them in order and click merge. It works the same way on Windows, macOS, Linux, Android and iOS, because it runs in the browser.
The important detail is where the merging happens. Most online PDF sites upload your documents to their servers. Ours does the work in your browser with JavaScript, so the files never leave your device. For contracts, payslips and medical letters, that difference matters more than any feature.
Windows
Windows has no built-in “combine PDFs” command. Microsoft Edge can open and print PDFs, but not merge them. Your options are:
- A browser tool, as above. No installation, works on locked-down work laptops.
- Adobe Acrobat: the merge feature (“Combine Files”) is part of the paid Acrobat Pro or Standard plans, not the free Reader.
- Free desktop apps such as PDFsam Basic or PDF24 Creator. Both are reliable. Download them only from the official sites, because PDF tools are a favourite disguise for adware.
Mac
macOS has the best built-in option of any system, hidden in Preview:
- Open the first PDF in Preview.
- Show the sidebar with View, then Thumbnails.
- Drag the other PDF files from Finder into the thumbnail sidebar, exactly where you want them.
- Choose File, then Export as PDF, to save a new combined file.
Two tips: drop files between thumbnails, not on top of one, or Preview may insert them in the wrong place. And use “Export as PDF” instead of plain Save, so the original stays untouched.
iPhone and iPad
The Files app can merge PDFs since iOS 15. Open Files, tap Select, choose the documents, tap the three-dot button and choose “Create PDF”. The order follows the order of the files in the folder, so rename them first (01, 02, 03) if the order matters.
If you need to reorder pages or combine PDFs with photos, a browser tool is easier: open it in Safari, pick the files from Files or Photos, and set the order with the arrows.
Android
Stock Android has no merge function. Google Drive lets you view PDFs but not combine them. A browser tool in Chrome is the simplest option and avoids installing yet another app with access to your storage. If you merge PDFs daily, a dedicated app can make sense, but check its permissions and reviews carefully.
Mistakes that ruin merged PDFs
Wrong order
Most tools merge in the order you selected the files, which is often alphabetical rather than logical. Always check the order before you click merge. Numbering files (01-cover.pdf, 02-letter.pdf) solves this once and for all.
A huge result
A merged PDF is roughly the sum of its parts. If one source is a 40 MB scan, the result will be at least 40 MB. Shrink scans before merging: re-scan at 200 to 300 DPI instead of 600, or turn photos into a PDF with compressed images using Compress Image and then JPG to PDF.
Printing to PDF instead of merging
“Print to PDF” turns every page into a new rendering. Links, form fields and selectable text can be lost, and quality may drop. A proper merge copies pages as they are.
Forgetting page numbers
Once five documents become one, readers lose track. After merging, run the file through Add Page Numbers so people can refer to “page 12” in a call.
Our take
For a one-off merge, do not install anything: on a Mac use Preview, everywhere else use a browser tool that processes files locally. Install desktop software only if you merge PDFs every day or need advanced features like bookmarks. And be wary of any “free” service that asks you to upload sensitive documents and then emails you a download link. There is no technical reason for that anymore.