# Merge PDFs — Merge PDF files on Mac

Combine PDFs into one, in the order you choose, or alternate pages to join front and back scans. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: PDF. Runs on your Mac; nothing is uploaded.

Drag PDFs into order and combine them into a single document. Pages keep their original quality, links and text. Scanned the fronts and backs of a stack separately? Alternate pages interleaves them into the right order, even when the backs were scanned last page first.

Page: https://www.onemactools.com/tools/merge-pdf · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Add your PDFs.** Drop two or more PDFs onto Merge PDFs. Or select them in Finder, right-click and choose Quick Actions › OMT: Merge PDFs.
2. **Put them in order.** Drag the files up and down the list. The merged PDF follows the order shown, top to bottom.
3. **Choose how to combine them.** Leave Order on One after another, or pick Alternate pages to interleave front and back scans.
4. **Click Merge.** One new PDF called Merged is saved in a dated folder in Downloads › OneMacTools. Use the Preview (eye) button to check it, or Show in Finder.

## Options
- **Order:** One after another puts every page of the first file, then every page of the next, and so on. Alternate pages (front & back scans) takes one page from each file in turn, so fronts 1, 2, 3 and backs 1, 2, 3 become 1, back 1, 2, back 2.
- **The second file is in reverse order (scanned back to front):** Only shown when Order is Alternate pages. On by default, because a stack turned over and fed through a scanner gives the backs last page first. Turn it off if your backs PDF is already in normal order.

## Tips
- Name your files with numbers first, like 01 Cover, 02 Report, so they land in the right order before you drag anything.
- For a double-sided paper stack, scan all the fronts to one PDF and all the backs to another, then use Alternate pages with the fronts file first in the list.
- A password-protected PDF can't be merged until it's unlocked. Run it through Remove Password first, then merge the unlocked copy.
- Merging doesn't make files smaller. If the result is too big to email, run it through Compress PDF afterwards.
- Add page numbers after merging, not before, so the numbers run on across the whole document.

## Questions
**How do I combine PDFs on a Mac?**
Drop the PDFs onto Merge PDFs, drag them into order and click Merge. You get one PDF with every page at its original quality, with text and links intact.

**How do I change the order of the files before merging?**
Drag them up or down in the file list. The merged PDF uses the list order from top to bottom.

**I scanned the fronts and backs separately. Can I put them in order?**
Yes. Choose Alternate pages and put the fronts file first, then the backs. If your scanner fed the backs last page first, keep “The second file is in reverse order” on.

**Is there a limit on files or pages?**
OneMacTools doesn't set one. The only limit is your Mac's memory.

**Why won't one of my PDFs merge?**
If it's password-protected, OneMacTools stops and names the file. Unlock it with Remove Password using the password you already have, then merge the copy.

**Can I merge only some pages of each file?**
Not in one step. Use Extract Pages on each file to keep the pages you want, then merge the extracted copies.