How to Merge PDF Files on Mac | Preview, Finder, Shortcuts and Terminal Compared

You don't need any third-party app to combine multiple PDFs into one on a Mac — the built-in Preview app, Finder Quick Actions, the Shortcuts app, and a hidden Terminal script can all do it. Each tool shines in a different scenario, so this article walks through "merging two or three PDFs quickly," "batch-processing dozens with a fixed order," and "automating a recurring task to one click." Compatible with macOS Sonoma / Sequoia, and the steps work the same on Apple Silicon and Intel Macs. For a broader look at Mac issues, see the Mac Troubleshooting Guide.

Quick guide: which method to use when
Merging PDFs in Preview (the basics) 1.How to merge two PDFs 1.How to merge multiple PDFs at once 1.Reorder and delete pages 1.Extract specific pages and merge them 1.Why you should always "Save As" after merging
One-click merging with Finder Quick Actions 1.Quick Action basics 1.Output filename and save location behavior 1.Tips for controlling the merge order
Automating merge tasks with the Shortcuts app 1.How to use the "Make PDF" action 1.Register it as a Finder Quick Action 1.Launch from the Dock or menu bar
Terminal command for batch merging 1.Location and basic syntax of join.py 1.Merging files in a specific order
What to do when merging fails 1.Remove password protection first 1.When the file is too large 1.Compress the merged PDF with a Quartz Filter 1.Fixing "can't open file" errors
Things to watch for before using online merge tools
Summary: which method by scenario

Quick guide: which method to use when

To get straight to the point, the Mac has four built-in ways to merge PDFs. Each excels in a different situation, so pick the one that fits your task first.

Preview: The classic for visually merging 2–10 PDFs while watching the page order. Intuitive GUI workflow
Finder Quick Actions: Select multiple PDFs in Finder and right-click once to merge. Files are ordered by filename, so it's the fastest option if your naming convention is tidy
Shortcuts app: For automating repetitive tasks. Build it once, run with one click going forward
Terminal (join.py): When you need to batch-process dozens of PDFs whose filenames don't sort nicely, or chain the merge into a shell script

If your task is just "combine two PDFs into one," go straight to Preview. Use Quick Actions when you want to stay inside Finder, Shortcuts when the same task comes up repeatedly, and Terminal for everything else.

Merging PDFs in Preview (the basics)

Preview, the standard Mac app, opens automatically when you double-click a PDF. Just drag a file into the thumbnails pane and you've merged it.

How to merge two PDFs

Open the first PDF in Preview (double-click it)
From the menu bar, choose View → Thumbnails (or press Option + Cmd + 2) to show the thumbnails pane
From Finder, drag the second PDF into the thumbnails pane
Once the second PDF's pages appear in the thumbnails, press Cmd + S to save (we recommend Save As, see below)

Where you drop matters. If you drop between two existing pages (you'll see a thin separator line), the new PDF is inserted at that point. If you drop directly on top of an existing thumbnail, Preview interprets it as "replace this page" — so always drop in the gap, never on a page.

How to merge multiple PDFs at once

You can merge three or more PDFs by dragging them in succession.

Open the first PDF and show the thumbnails pane
In Finder, Cmd-click to multi-select the second, third, and so on
Drag the entire selection onto the thumbnails pane
Verify the order, then drag thumbnails to reorder if needed
Use File → Export to save the result under a new filename

When you drag multiple files at once, the order tends to follow your selection order in Finder, but it isn't 100% reliable. Always confirm the final sequence in the thumbnails pane.

Reorder and delete pages

To rearrange pages after merging, just drag thumbnails in the pane.

Reorder: Drag a thumbnail to its new position. Use Shift / Cmd to select a range and move them together
Delete: Select a thumbnail and press Delete, or right-click → "Delete"
Rotate: Select a thumbnail and press Cmd + R (clockwise) or Cmd + L (counter-clockwise)

If your source PDFs mix portrait and landscape orientations, rotating before saving makes the result look consistent.

Extract specific pages and merge them

"Take just pages 3–5 of one PDF and merge them with another" — Preview alone handles this too.

Open the source PDF in Preview
In the thumbnails pane, Cmd-click only the pages you need
Open File → Print, click PDF ▼ → Save as PDF at the bottom-left of the dialog (if Print isn't available, use File → Export instead)
Save the extracted PDF under a new filename
Use that extracted PDF as input for the merge steps above

You can also drag thumbnails directly into another open Preview window's thumbnails pane. Lining up multiple Preview windows side by side makes it easy to pull out only the pages you need and assemble a new PDF.

Why you should always "Save As" after merging

If you press Cmd + S after merging, Preview overwrites the first PDF you opened. To preserve the original, use one of these instead:

File → Duplicate (Option + Shift + Cmd + S), then save the copy
File → Export with a new filename and location
Hold Option while opening the File menu — "Save As…" appears

Especially for work documents, overwriting the original makes it impossible to swap files back. Saving as "merged.pdf" or similar under a new name is the safe operating procedure.

One-click merging with Finder Quick Actions

Since macOS Mojave, Finder has a feature called Quick Actions built in. You can select multiple PDFs and merge them with a single right-click — no need to open Preview.

Quick Action basics

In Finder, select multiple PDFs (Cmd-click for individual selection or Shift to select a range)
Right-click and choose Quick Actions → Create PDF
The merged new PDF file is created in the same folder as the first selected file

If Quick Actions doesn't appear in the right-click menu, open Finder's View → Show Preview (Shift + Cmd + P) to show the Preview pane, then click More… at the bottom of the action buttons and enable "Create PDF."

Output filename and save location behavior

The "Create PDF" Quick Action follows these rules for output:

The output filename is the first selected file's name with a .pdf extension (e.g., if invoice.pdf was first, the result is also invoice.pdf)
If a file with that name already exists, a number is appended like "invoice 2.pdf"
The save location is the same folder as the first selected file. Working on the Desktop or Downloads makes it immediately visible

Since the filename can be confusing, we recommend renaming after merging. In Finder, just press Enter to rename right away.

Tips for controlling the merge order

Quick Actions merges by Finder's display order, not your selection order. Take advantage of this by adding numeric prefixes (01_, 02_…) to filenames so they merge in the desired order when Finder is set to "Sort by Name."

Sort by name: Choose Finder's "View → Clean Up By → Name"
Bulk-rename with sequential numbers: Select multiple files → right-click → "Rename Items…" → pick "Format" with "001, 002…" to add sequential numbers in one shot
For chronological order use Date; for size use Size before selecting

Conversely, if you have a group of files that "must be in a certain order" (e.g., A.pdf needs to be last), the quickest fix is renaming it temporarily to 09_A.pdf.

Automating merge tasks with the Shortcuts app

The Shortcuts app, standard since macOS Monterey, can automate PDF merging too. Build it once and you can launch it with a single click from Finder's right-click menu or the menu bar — perfect for tasks you do repeatedly.

How to use the "Make PDF" action

Open the Shortcuts app and click the + button in the upper left to create a new shortcut
In the right-side search bar, search for Make PDF and drag it in
Above the "Make PDF" action, add Receive Input and set the input type to "Files"
Below the "Make PDF" action, add a Save File action and set the save destination (e.g., Desktop)
Click the ⓘ (info) button in the top right → check Use as Quick Action → enable Finder
Rename the shortcut (e.g., "Merge PDFs") and save

Now Finder's right-click menu shows "Quick Actions → Merge PDFs."

Register it as a Finder Quick Action

With the Quick Action toggle enabled in step 5 above, you can select multiple PDFs in Finder, right-click, and run "Merge PDFs."

Unlike the standard Create PDF Quick Action, the Shortcuts version lets you customize the save location, filename, and PDF metadata however you want. For example, you can build "Save the merged file to a specific folder in iCloud Drive" or "Open the merged PDF in another app" into a single step.

Launch from the Dock or menu bar

Right-click your shortcut in the Shortcuts app to Add to Dock or Pin in Menu Bar.

Dock: Click the Dock icon to bring up a file picker, then run the merge
Menu bar: Click the Shortcuts icon in the menu bar to run with one click
Keyboard shortcut: System Settings → Keyboard → Keyboard Shortcuts → "Services" lets you assign any key combo

If you prefer to keep your hands on the keyboard, see Mac Keyboard Shortcuts for a broader cheat sheet.

Terminal command for batch merging

If you need to script the merging of dozens of PDFs or chain it with other shell commands, calling the built-in join.py script directly from Terminal is the most flexible. No additional Python install is required, and it's in the same place on Apple Silicon and Intel Macs.

Location and basic syntax of join.py

The script is located at:

/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join.py

The basic syntax is:

"/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join.py" -o output.pdf input1.pdf input2.pdf input3.pdf

-o: Specify the output filename
input*.pdf: Source PDFs listed left to right (the page order in the output follows this order)
If a path contains spaces, wrap it in quotes (as shown above with "…")

If you'll use this often, set an alias in ~/.zshrc like alias pdfjoin='"/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join.py"' so you can write the shorter pdfjoin -o out.pdf 1.pdf 2.pdf.

Merging files in a specific order

Using shell wildcards lets you merge every PDF in a folder.

"/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join.py" -o all.pdf *.pdf

In this case, the shell expands the wildcard in alphabetical order before passing it to the script. To force a specific sequence, the same trick as Quick Actions — give files numeric prefixes (01_intro.pdf, 02_main.pdf, …) — works perfectly.

For complete control over the order, list the files explicitly:

"/System/Library/Automator/Combine PDF Pages.action/Contents/MacOS/join.py" -o report.pdf cover.pdf chapter1.pdf chapter2.pdf appendix.pdf

You can also wrap this in a shell script — easy to set up, for example, "every night merge all PDFs in this folder."

What to do when merging fails

"Dropping into the thumbnails doesn't add a page." "Quick Actions errors out." "The merged file won't open." Here are the typical PDF merge problems and their fixes.

Remove password protection first

Encrypted PDFs and PDFs with editing restrictions can refuse to merge or be added to thumbnails. If you see "can't merge," check for password protection or editing restrictions first.

Open the PDF in Preview and choose File → Export
Uncheck Encrypt at the bottom of the export dialog and save
Use the resaved PDF (now unencrypted) for merging

If you don't know the editing password, get it from the document owner or use a third-party tool. Removing security passwords without permission may violate the rights holder's intent, so confirm you have authority before proceeding.

When the file is too large

For PDFs of several hundred MB to a few GB, both Preview and Quick Actions can hang on memory. Workarounds:

Split, then merge: Use Preview to "export each page separately" first, then process in stages
Use Terminal: join.py often has better memory efficiency
Delete unnecessary pages first: Remove blank pages from scanned PDFs before merging
Free up RAM: Close other apps to gain available memory

Compress the merged PDF with a Quartz Filter

If the merged PDF is too big to email, you can compress it with a Quartz Filter.

Open the merged PDF in Preview
Choose File → Export
From the Quartz Filter dropdown, pick Reduce File Size
Save under a new name (image quality drops, so always keep the original separately)

The default "Reduce File Size" can compress aggressively, sometimes degrading image-heavy PDFs noticeably. To compress while preserving quality, you can also build a custom Quartz Filter in ColorSync Utility and tune the resolution and quality parameters.

Fixing "can't open file" errors

If any of the source PDFs is corrupt, the merge itself can succeed but the output file may not open.

Open each source PDF individually in Preview: any that won't open is the culprit
For suspect PDFs, re-export from the original creating app, then re-merge
If Quick Actions or Shortcuts errors out, switch to Preview for a more detailed error message
If Preview crashes during the merge, try 5 Ways to Force Quit Apps on Mac to restart it before retrying

Things to watch for before using online merge tools

Search "merge PDF Mac" and you'll find plenty of online tools that let you upload PDFs in a browser and merge them. They're convenient but carry several risks for business use.

Confidential information leaks: Uploaded PDFs end up on overseas servers. Many companies forbid online tools for internal documents, customer info, or contracts
File size and frequency limits: Free versions often cap at a few uses per day or 10MB per file
Ads and tracking scripts: Some sites are loaded with banner ads and trackers
Privacy policy claims: "Files are auto-deleted after X hours" — but the deletion isn't technically verifiable to the user

The four methods in this article (Preview, Quick Actions, Shortcuts, Terminal) all run entirely on your Mac, so files never leave your machine. Always merge sensitive documents offline.

Summary: which method by scenario

Final summary by use case:

Visually merging 2–10 PDFs: Preview (drag-and-drop)
Stay inside Finder, right-click only: "Create PDF" Quick Action
Same merge task every week: Shortcuts app + register as Quick Action
Batch-process dozens with a script: Terminal calling join.py
Confidential PDFs: Limit yourself to one of the offline methods above (online tools not recommended)

Most merge problems trace back to password protection and file corruption. When you hit an error, open each source individually in Preview to verify it first, then retry. For Mac issues in general, see the Mac Troubleshooting Guide.