📄 + 📄 = 📖
Complete Guide Updated: January 2025 12 min read

How to Merge PDF Files: Complete Guide (2025)

To merge PDF files, upload your documents to a PDF merger tool, arrange them in the desired order, and click merge. The fastest free method is using a browser-based tool like RaptorPDF's Merge PDF, which combines files locally without uploading them to any server. Simply drag your PDFs, reorder if needed, and download your combined document in seconds. This guide covers all methods including online tools, Adobe Acrobat, Preview on Mac, and command-line options.

In This Guide

Quick Steps: Merge PDFs in 3 Steps

Need to combine PDFs right now? Here's the fastest method using a free online tool:

1 Upload Your PDF Files

Go to RaptorPDF's Merge PDF tool. Drag and drop multiple PDF files onto the upload area, or click to browse your files. You can add as many documents as you need - there's no limit on the number of files.

2 Arrange the Order

Your files appear as draggable cards. Drag and drop to reorder them in the sequence you want. The final merged PDF will follow this order, with the first file's pages appearing first. Preview thumbnails help you verify the arrangement.

3 Merge and Download

Click the Merge button to combine all PDFs into one document. The process takes just seconds. Download your merged PDF immediately - no email required, no watermarks added, quality fully preserved.

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No signup required. No watermarks. Unlimited files.

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Why You Might Need to Merge PDFs

Combining multiple PDF files into a single document is one of the most common PDF tasks. Here are the most frequent use cases:

📝 Compile Reports

Combine monthly reports, quarterly analyses, or annual summaries into one comprehensive document.

📚 Create Portfolios

Merge work samples, certificates, and resumes into a professional portfolio.

📦 Consolidate Invoices

Combine multiple invoices or receipts for expense reports or tax filing.

📄 Assemble Contracts

Merge contract pages, appendices, and signature pages into one legal document.

🎓 Combine Study Materials

Merge lecture notes, handouts, and study guides for easier review.

📷 Photo Collections

Combine scanned photos or image-based PDFs into albums or presentations.

Beyond these specific scenarios, merging PDFs helps with organization, reduces file clutter, and makes sharing multiple documents much simpler. Instead of attaching 10 files to an email, you can send one consolidated PDF.

Method 1: Merge PDFs Online (Free)

Browser-based PDF tools offer the fastest and most convenient way to merge documents. No software installation required, and the best tools process files locally for complete privacy.

Using RaptorPDF (Recommended)

RaptorPDF's merge tool works entirely in your browser. Your PDFs never leave your device, making it ideal for sensitive documents like contracts or financial records.

  1. Open RaptorPDF Merge PDF
  2. Drag multiple PDF files onto the page or click to upload
  3. Drag to reorder files in your preferred sequence
  4. Click "Merge" then "Download"

Advantages

  • 100% free, no signup
  • Files processed locally (private)
  • No watermarks on output
  • Works on any device
  • Unlimited file count

Limitations

  • Free tier: 10MB per file
  • Requires internet connection
  • Very large files may be slower

Pro Tip: When merging many files, name them with numbers (01-intro.pdf, 02-chapter1.pdf) to make ordering easier. Most tools sort by filename initially.

Method 2: Using Adobe Acrobat

Adobe Acrobat is the industry-standard PDF editor with powerful merging capabilities. However, it requires a paid subscription ($22.99/month for Acrobat Pro).

Adobe Acrobat Pro/DC Steps

  1. Open Adobe Acrobat
  2. Go to Tools > Combine Files
  3. Click Add Files and select your PDFs
  4. Drag to reorder files or use the arrow buttons
  5. Click Combine to merge
  6. Save your new combined PDF

Advantages

  • Professional-grade tool
  • Works offline
  • Advanced page manipulation
  • Can merge non-PDF files too

Limitations

  • Expensive ($22.99/month)
  • Requires installation
  • Overkill for simple merging
  • Free Reader can't merge

Adobe Acrobat Reader (the free version) cannot merge PDFs - you need Acrobat Pro or Acrobat DC. For occasional merging, a free online tool is more practical and cost-effective.

Method 3: Using Preview on Mac

Mac users have a free built-in option: Preview can merge PDFs without any additional software. This method works well for combining a few documents.

Preview (macOS) Steps

  1. Open the first PDF in Preview
  2. Go to View > Thumbnails to show the sidebar
  3. Drag additional PDF files into the sidebar (position them where you want)
  4. Arrange pages by dragging thumbnails
  5. Go to File > Export as PDF to save the merged document

Advantages

  • Free (built into macOS)
  • No internet needed
  • Page-level control
  • No watermarks

Limitations

  • Mac only
  • Can be confusing with many files
  • May corrupt complex PDFs
  • No batch processing

Important: When using Preview, make sure to use "Export as PDF" rather than just "Save." Using Save may overwrite your original first PDF with the merged version.

Method 4: Merging PDFs on Windows

Windows doesn't have a built-in PDF merger like Mac's Preview, but there are several options available:

Using Microsoft Edge

Microsoft Edge has limited PDF editing capabilities but cannot directly merge PDFs. You'll need to use an online tool or third-party software.

Using Microsoft Print to PDF

A workaround for tech-savvy users:

  1. Open all PDFs in separate Edge or Chrome tabs
  2. Use browser's print function (Ctrl + P)
  3. Select "Microsoft Print to PDF" as the printer
  4. Print each to a new PDF (pages get combined in the print queue)

This method is cumbersome and not recommended. For Windows users, online PDF mergers provide a much better experience.

Using Free Third-Party Software

Applications like PDFsam (PDF Split and Merge) offer free PDF merging on Windows. However, they require installation and may include ads or bundled software.

How to Merge Without Losing Quality

One of the most common concerns when merging PDFs is quality loss. Here's what you need to know:

The Good News: Quality is Typically Preserved

When PDFs are properly merged, the original quality is maintained because:

When Quality Might Degrade

Quality issues can occur if:

Best Practice: Always use a dedicated PDF merge tool like RaptorPDF rather than print-based methods. Check file sizes before and after - a properly merged PDF should be roughly the sum of the original file sizes. For more details, see our guide on merging PDFs without losing quality.

How to Reorder Pages When Merging

Sometimes you need more control than just arranging files - you need to reorder individual pages. Here's how to handle different scenarios:

Reordering Whole Documents

All PDF merge tools let you drag and drop files to change their order before merging. The first file in the list becomes the first pages of your merged PDF.

Reordering Individual Pages

For page-level control, you have two approaches:

  1. Before merging: Use the PDF organizer to reorder pages within each document first
  2. After merging: Merge first, then use a page reordering tool to arrange pages in the final document

Interleaving Pages

If you need to alternate pages from two documents (like front/back of scanned pages), some advanced tools offer interleaving. For most users, the easiest approach is to merge then reorder manually.

Tool Comparison: Which Method is Best?

Here's how the different PDF merging methods compare:

Feature RaptorPDF Adobe Acrobat Preview (Mac) PDFsam
Price Free $22.99/mo Free Free
Works Online Optional
No Installation
Drag & Drop Reorder
Preserves Quality
Privacy (Local)
No Watermarks
Cross-Platform Mac only
Best For Most users Power users Mac users Offline Windows

Why RaptorPDF for PDF Merging

RaptorPDF is designed with both simplicity and privacy in mind. Here's what makes it stand out for merging PDF files:

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Combine multiple PDF files into one in seconds. Free, private, no signup required.

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Frequently Asked Questions

Can I merge PDF files for free?

Yes, you can merge PDF files completely free using browser-based tools like RaptorPDF. No software installation, no signup, and no watermarks on the output file. Most free tools support merging 10-20 files at once, which covers the vast majority of use cases.

Will merging PDFs reduce the quality?

No, properly merging PDFs does not reduce quality. Quality-focused tools like RaptorPDF combine PDF files without recompressing or altering the content. Your text, images, and formatting remain exactly as they were in the original documents. Avoid "print to PDF" methods as these can degrade quality.

How do I merge PDFs in a specific order?

Upload all your PDF files to the merge tool, then drag and drop them into the sequence you want. Most tools display your files as cards or thumbnails that can be easily reordered. The final PDF will follow the order shown, with the first file's pages appearing first.

Can I merge PDFs on my phone?

Yes, browser-based PDF mergers like RaptorPDF work perfectly on smartphones and tablets. Simply open the tool in your mobile browser, tap to upload your files, and merge. No app installation required - it works in Safari, Chrome, or any mobile browser.

How many PDFs can I merge at once?

RaptorPDF's free tier allows merging up to 10 files at once, with each file up to 10MB. Pro users have no limits on file count or size. If you need to merge more than 10 files, you can merge in batches and then merge the resulting files together.

Can I merge password-protected PDFs?

Yes, if you know the passwords. When you upload a password-protected PDF, you'll be prompted to enter the password. Once unlocked, the PDF can be merged with other documents. If you don't have the password, the PDF cannot be merged due to its security protection.