Need to combine multiple PDF files into one on your Mac? You have 3 options: Preview (built-in), LocalKit (web-based, private), or Terminal (advanced). This guide shows you all three methods step-by-step.
Method 1: Using Preview App (Built-in, Free)
Preview is macOS's built-in PDF viewer. It's already on your Mac and works well for basic PDF merging.
Step-by-Step Instructions:
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Open first PDF in Preview
Double-click the first PDF file. It opens in Preview automatically.
-
Show Thumbnails sidebar
Click View → Thumbnails (or press
⌘+Option+2). You'll see page thumbnails on the left. -
Drag other PDFs into sidebar
From Finder, drag the second PDF file into the thumbnail sidebar. Drop it where you want it to appear.
-
Repeat for all PDFs
Keep dragging PDFs into the sidebar until all files are combined.
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Save merged PDF
File → Export as PDF. Choose location and click Save.
✅ Pros
- Free (built into macOS)
- No internet required
- Works offline
❌ Cons
- Slow for many files
- Clunky interface
- Can crash with large PDFs
Method 2: Using LocalKit (Fastest, Private)
LocalKit's PDF Merge tool is faster than Preview and doesn't upload your files to any server.
Step-by-Step Instructions:
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Open LocalKit PDF Merge
Go to localkit.app/pdf-merge
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Drop PDF files
Drag all PDFs into the drop zone (or click to browse). You can add 2, 10, or 100 PDFs at once.
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Reorder if needed
Drag files up/down to change the order.
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Click "Merge PDFs"
Processing happens instantly in your browser.
-
Download merged file
Click download. Your merged PDF is ready.
🔒 Privacy Note
LocalKit processes PDFs entirely in your browser. Your files never get uploaded to any server. This is perfect for confidential documents like contracts, NDAs, or financial statements.
✅ Pros
- Fastest method (instant processing)
- 100% private (no upload)
- Handles unlimited files
- No file size limit
- Works on any browser
❌ Cons
- Requires internet (first load)
- Not a native Mac app
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Merge your PDFs in seconds. No upload, no registration, 100% free.
Merge PDFs for Free →Method 3: Using Terminal (Advanced Users)
For developers or power users, you can merge PDFs using the command line.
Step-by-Step Instructions:
-
Open Terminal
Applications → Utilities → Terminal (or press
⌘+Spaceand type "Terminal") -
Navigate to PDF folder
cd ~/Documents/PDFs -
Run merge command
/System/Library/Automator/Combine\ PDF\ Pages.action/Contents/Resources/join.py -o merged.pdf file1.pdf file2.pdf file3.pdf
✅ Pros
- Scriptable (for automation)
- No GUI needed
- Built into macOS
❌ Cons
- Requires Terminal knowledge
- Easy to make typos
- Not user-friendly
Which Method Should You Use?
| Preview | LocalKit | Terminal | |
|---|---|---|---|
| Speed | ⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| Privacy | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ |
| Ease of Use | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐ |
| File Limit | ~20 files | Unlimited | Unlimited |
| Best For | 2-5 files | Any number | Automation |
Our recommendation: Use LocalKit for most tasks. It's the fastest, easiest, and handles unlimited files. Use Preview only if you're offline and have just 2-3 PDFs. Use Terminal only if you're automating with scripts.
Frequently Asked Questions
Can I merge password-protected PDFs?
Yes, but you'll need to unlock them first. In Preview, open the PDF and enter the password. In LocalKit, you'll be prompted for the password before merging.
Is there a file size limit?
Preview can struggle with PDFs over 100MB. LocalKit has no file size limit - the only constraint is your computer's available memory.
Will the quality be affected?
No. All three methods preserve the original quality. PDFs are simply combined without any compression.
Can I merge PDFs and images together?
Preview: Yes, drag images into the sidebar alongside PDFs.
LocalKit: Convert images to PDF first using our Image to PDF tool.
Terminal: Requires additional steps.
Does this work on older macOS versions?
Yes. Preview has been included in every macOS version since OS X. LocalKit works on any Mac with a modern browser (Safari 14+, Chrome, Firefox).
Conclusion
Merging PDFs on Mac is easy with the right tool. For most users, we recommend LocalKit's PDF Merge tool - it's faster than Preview, completely private, and handles unlimited files for free.
Got questions? Leave a comment below or contact us.