Merging and splitting PDFs on a Mac is mostly a Preview job. The catch is that Preview’s controls are hidden behind a sidebar most people never open, so the common belief is that macOS cannot do it.

Merge with Preview

  1. Open the first PDF in Preview.
  2. Choose View → Thumbnails to show the page sidebar.
  3. Open the second PDF in another Preview window, also with thumbnails shown.
  4. Drag pages from the second window’s sidebar into the first, dropping them where they should go.
  5. Save.

Drag a whole document’s worth of pages by selecting them all first, or drag the file itself onto the sidebar to append every page.

The result is a single PDF in the order you arranged it. Nothing is re-encoded, so quality is unchanged and file size is roughly the sum of the sources.

Split with Preview

  1. Open the PDF and show thumbnails.
  2. Select the pages you want in the new document.
  3. Choose File → Print, then set the page range and choose Save as PDF from the PDF menu at the bottom of the print dialog.

That “print to PDF” step is the standard way to extract pages, and it is the only way Preview offers. It re-renders the pages, which is fine for text and can soften very high-resolution images.

For a mechanical split of a fixed number of pages, the command line is more precise:

# pages 1-10 into a new file
/System/Library/Automator/Split\\ PDF\\ Pages.action/Contents/MacOS/SplitPDFPages \
  input.pdf --pages 1-10 --out output.pdf

When Preview Is Not Enough

Preview cannot reorder pages by typing a number, rotate a subset permanently, compress images, or add bookmarks. It also cannot handle a 500-page document comfortably — the thumbnail sidebar gets slow.

PDF Expert is the general editor: page management, annotations, text and image editing. PDF Reader Pro covers the same ground with more emphasis on forms and conversion. UPDF is the lighter, cheaper option for reading and annotating with basic editing.

Our guide to Mac PDF editors compares what each one actually does, which matters because “PDF editor” covers everything from an annotator to a layout tool.

The Step People Forget

A merged PDF inherits the page sizes of its sources. Combine a letter-size document with an A4 one and the result has two page sizes, which prints badly and looks wrong on screen.

Check before merging: open each source, press Command-I, and look at the page dimensions. If they differ, decide whether to scale one set first — most editors can do that, and Preview cannot.

The other habit worth having: keep the sources. A merged PDF is a new document, and unpicking it later means splitting by page range with no record of where each part came from.

Frequently Asked Questions

Can Preview merge PDFs without extra software?

Yes. Open one PDF, show the thumbnail sidebar, and drag another PDF's pages into it. Preview then saves the combined document. It is not obvious from the interface, which is why most people assume it needs a paid tool.

How do I make a merged PDF smaller?

Merging does not recompress anything, so the result is roughly the sum of its parts. Reducing size requires a separate compression pass, which most PDF editors offer and Preview does not.