PDFs and conversion

How to combine PDF files on a Mac without uploading them

Updated 25 October 2026 · 3 min read

Preview and Finder can combine PDF files for free, with a few traps. Here is how each works, how to reorder, rotate and remove pages, and how Orrel merges into a new file and leaves the originals alone.

Combining PDFs is one of the most common reasons people upload private documents to websites. There is no need: macOS can merge PDFs itself, and once you know Preview's habits it is quick.

Merge in Preview

1. Open the first PDF in Preview. If you want to keep it unchanged, choose File › Duplicate and work in the copy.
2. Choose View › Thumbnails to show the page sidebar.
3. Drag the second PDF's icon from Finder into the sidebar, dropping it where you want its pages to go. To bring in only some pages, open both PDFs with thumbnails showing and drag pages from one sidebar to the other. ⌘-click to select several.
4. Drag thumbnails to reorder them.
5. Close the window or choose File › Save. Preview saves to the file you started with.

The same sidebar handles the rest of the tidying up:

• Rotate. Select a thumbnail and press ⌘R to rotate right or ⌘L to rotate left.
• Remove. Select a thumbnail and press Delete.
• Extract. Drag a thumbnail out to the desktop to make a one-page PDF.

The trap. Preview edits in place and saves automatically. Duplicate first, or you will find the first PDF has quietly become the merged one.

Merge from Finder

For a quick merge with no page editing, select the PDFs (and images, if you like) in Finder, Control-click and choose Quick Actions › Create PDF. A new PDF appears beside the files. Check the page order afterwards, and if it is wrong, open the result in Preview and drag the pages round.

Things that go wrong

• The merged file is huge. Combining scans adds up their sizes, and Preview sometimes saves a larger file than the parts. See how to reduce a PDF's size.
• One PDF will not open. A PDF protected with an opening password must be unlocked with its password first.
• Form fields or signatures disappear. Some interactive features do not survive being merged. Keep the original signed copy.

How Orrel does it

Orrel's PDF workspace shows every page of every file you drop in as a thumbnail on one board. Drag pages into order across files, turn the sideways ones, delete the blank ones, then choose Save Merged PDF. Images dropped in become pages too, which makes it easy to combine a scan with photos of receipts.

• Originals untouched. The merged PDF is written as a new file beside the first original. Nothing is saved over a file you dropped in.
• The other jobs, same board. Extract the pages you have selected, split a PDF into single pages, add a password, or compress the result.
• Size reported. When you save, Orrel tells you the page count and file size, so a surprisingly large result is obvious.
• Protected PDFs. Open one with its password, and Orrel can include it in a merge.

If you use an AI assistant connected to Orrel, it can do the same thing on request: "merge the three lease PDFs in Downloads, then compress the result" runs on your Mac and writes new files.

Where Orrel stops

Orrel arranges pages; it does not edit what is on them. There is no text editing, form filling, signing or annotation. Re-saving through macOS can make some PDFs larger than the originals, and Orrel tells you when that happens rather than hiding it. For text edits and form work, a dedicated PDF editor is the right tool.