Merge PDFs on your Mac into one file, offline
By Himanshu Ranjan · Updated 8 November 2026
To merge PDFs on a Mac with FileDial, select the files in Finder in the order you want, hold the right Option key and choose Combine › Merge PDFs. One new PDF appears beside the originals. Choose Merge with bookmarks to keep each file findable, or Binder with cover and contents for a bundle with a contents page. It all happens on your Mac, with nothing uploaded.
How to do it with FileDial
- In Finder, select the PDFs in the order you want them to appear.
- Hold right ⌥ to open the dial.
- Choose Combine › Merge PDFs, or Combine › Merge with bookmarks to get a bookmark per file.
- For a cover and contents page, choose Combine › Binder with cover and contents… and follow the prompt.
- Open the new PDF beside the originals; use Undo if the order needs changing.
Your original file stays untouched. The result is saved beside it, and every result has Undo.
Which option to pick
| Tool | Use it when |
|---|---|
| Merge PDFsCombine | The quickest join: one new PDF with the files in the order you selected them. |
| Merge with bookmarksCombine | One PDF with a bookmark per file, named after it, so readers can jump between documents. |
| Interleave fronts and backsCombine | You scanned one side, then the other: first PDF is fronts, second is backs, output is in page order. |
| Binder with cover and contents…Combine | Building a packet: adds a cover, a contents page with page numbers, then every file with bookmarks. |
Getting the order and structure right
Merging sounds trivial until you open the result and find the appendix before the cover letter. FileDial uses selection order, so the simplest habit is to Command-click the files one by one in the order you want them. Numbering file names first (01, 02, 03) is another reliable way to keep a long set straight.
Think about who reads the merged file. A plain merge is fine for yourself, but a reviewer working through a 60-page application will thank you for bookmarks: Merge with bookmarks adds one per source file, named after it, which shows up in the sidebar of most PDF readers. For formal bundles, such as a rental application or a submission pack, the binder tool adds a cover and a contents page with page numbers.
- Duplex scanning on a single-sided scanner: scan all fronts, flip the stack, scan all backs, then use Interleave fronts and backs.
- Mixed photos and PDFs: see combining images into a PDF instead.
- Large result: run a compression tool on the merged file afterwards.
Why merging online is a poor trade for personal paperwork
The files people merge are often a whole life in one bundle: pay slips, bank statements, an ID and a reference letter for a mortgage or a flat. A merger site receives every piece at once. That is exactly the kind of collection that leaked when, as Cybernews reported in July 2024, PDF Pro and Help PDF left Amazon S3 storage open and exposed 89,062 user-uploaded files, among them passports, IDs, certificates and contracts.
The FBI Denver Field Office warned in March 2025 that free online document tools can scrape personal data such as identity numbers, banking details, emails and passwords. With FileDial the merge happens on your Mac and works with Wi-Fi off.
Other ways to merge PDFs on a Mac
Preview can merge PDFs for free. Open the first PDF, show the sidebar with View › Thumbnails, then drag other PDFs into the thumbnail list where you want their pages to go, and save. Finder can also make one PDF from several files: select them, Control-click and choose Quick Actions › Create PDF.
Those work well for two or three files. FileDial is quicker when you merge often or need structure: one gesture from Finder, bookmarks per file, interleaving for duplex scans, a binder with a contents page, and Undo on every result. The originals are never changed.
Questions
In what order are the PDFs merged?
In the order you selected them in Finder. Command-click files one at a time to set the order, or number the file names first. If it comes out wrong, Undo removes the merged file and you can try again.
Can I merge PDFs without internet?
Yes. All FileDial tools run on your Mac and work with Wi-Fi off. Your files are never uploaded, so there is no size cap from a website either.
Will merging reduce quality?
Merge tools combine the pages into one new PDF; the note for these tools describes no image compression. If the merged file is too large to send, run Compress › Email-safe (under 20 MB) on it afterwards.
Can I merge front and back scans into one document?
Yes. Select the PDF of fronts first and the PDF of backs second, then choose Combine › Interleave fronts and backs. You get one PDF with the pages in reading order.
How much does it cost?
There is a 1-day free trial with every tool, no card and no account. Then it is $20 once for a lifetime licence on 2 Macs, with a 14-day refund.