How to Merge and Split PDFs: The Complete Guide

Two Operations, Endless Use Cases

Merging and splitting PDFs are the two most common document management tasks after creating and reading them. Merging combines multiple PDF files into a single document. Splitting breaks a single PDF into multiple smaller files. Together, they give you complete control over how your documents are organized, shared, and archived.

Despite how fundamental these operations are, many people still struggle with them. Adobe Acrobat charges a subscription. Free tools are often riddled with ads, impose file size limits, or add watermarks. Operating system preview apps sometimes work but lack precision controls.

This guide covers both operations in depth: how they work, when to use each one, step-by-step instructions, and advanced techniques for complex document management scenarios. Whether you are combining reports for a board meeting or extracting a single chapter from a textbook, you will find a clear workflow here.

Merge vs Split: When to Use Each

Understanding when to merge and when to split helps you plan your document workflow before you start.

How to Merge PDFs: Step-by-Step

Using the Online Merge Tool

The merge PDF tool on ConvertIntoMP4 combines multiple PDF files into a single document while preserving formatting, hyperlinks, bookmarks, and form fields.

Step 1: Upload your PDF files.

Navigate to the merge PDF tool and upload the files you want to combine. You can select multiple files at once or add them one at a time. Supported input: PDF files of any size.

Step 2: Arrange the order.

After uploading, your files appear in a list. Drag and drop to reorder them. The final merged document will follow this sequence -- the first file in the list becomes the first pages of the output, and so on.

Step 3: Configure options.

Optional settings may include:

• Table of contents generation. Automatically create bookmarks at the start of each source document.
• Page numbering. Add consecutive page numbers across the merged document.
• Metadata. Set the title, author, and subject for the merged output.

Step 4: Merge and download.

Click the merge button. The tool processes all files and produces a single combined PDF. Download the result.

Merge Best Practices

Check file sizes before merging. If you are combining several large PDFs (scanned documents, image-heavy presentations), the output file can be very large. Consider compressing individual files first using the compress PDF tool, or compress the merged output afterward.

Verify page order after merging. Open the merged PDF and scroll through to confirm that pages from each source file appear in the correct sequence. Pay special attention to boundaries between source documents.

Preserve bookmarks. If the source PDFs contain bookmarks (table of contents entries), a good merge tool preserves them and optionally nests them under new top-level bookmarks for each source document.

Handle mixed page sizes. Source PDFs may have different page dimensions (Letter vs A4, portrait vs landscape). The merge tool preserves each page at its original size. If you need a uniform page size, convert individual files first.

How to Split PDFs: Step-by-Step

Using the Online Split Tool

The split PDF tool breaks a single PDF into multiple files. You control exactly how the document is divided.

Step 1: Upload your PDF.

Navigate to the split PDF tool and upload the document you want to divide.

Step 2: Choose a split method.

Common split options include:

• Split into individual pages. Creates one PDF per page. A 20-page document produces 20 single-page PDFs.
• Split by page ranges. Specify custom ranges like "1-5, 6-10, 11-20" to create three separate files.
• Split at specific pages. Define split points: "split after page 3, 7, and 15" creates four files.
• Split by file size. Divide a large PDF into chunks of approximately equal file size (useful for email attachment limits).
• Extract specific pages. Pull out only the pages you need, discarding the rest.

Step 3: Split and download.

The tool processes the PDF and produces the specified output files. For multiple outputs, they are typically provided as a ZIP archive for convenient downloading.

Split Methods Explained

Extracting Specific Pages

Sometimes you do not need to split a document into multiple parts -- you just need to extract a few specific pages. The extract pages from PDF tool is designed for this use case. Upload your PDF, select the pages you want (individually or as ranges), and download a new PDF containing only those pages.

This is particularly useful for:

• Extracting a specific invoice from a monthly billing statement
• Pulling out a particular form from a government document package
• Getting a single slide from a PDF presentation
• Saving a specific section of a manual or textbook

Advanced Techniques

Rearranging Pages Within a Document

Merging and splitting are not just about combining and separating files -- they are building blocks for reorganizing documents. To rearrange pages within a single PDF:

1. Split the PDF into individual pages
2. Rename or reorder the individual page files
3. Merge them back together in the desired order

Or, use the organize PDF tool which provides a visual drag-and-drop interface for reordering pages without the split-and-merge workflow.

Removing Unwanted Pages

To delete specific pages from a PDF:

1. Identify the pages you want to keep
2. Extract those pages using the extract pages from PDF tool
3. The resulting file contains only the pages you selected

This is cleaner than splitting and merging because it is a single operation.

Interleaving Pages from Multiple Documents

A less common but occasionally necessary task is interleaving pages from two documents -- for example, combining the front and back scans of a double-sided document:

1. Split both source documents into individual pages
2. Alternate pages: Front page 1, Back page 1, Front page 2, Back page 2, etc.
3. Merge the alternated pages into a single document

Combining Different Document Types

What if you need to merge files that are not all PDFs? For example, combining a Word document, an Excel spreadsheet, and a PDF presentation into a single file:

1. Convert non-PDF files to PDF format first using the PDF converter
2. Merge the resulting PDFs using the merge tool

The document converter category page lists all supported input formats for PDF conversion.

Real-World Workflows

Workflow 1: Preparing a Contract Package

Situation: You need to send a client a single PDF containing an NDA, a service agreement, and two appendices. Each document exists as a separate PDF.

Steps:

1. Open the merge PDF tool
2. Upload the four documents in order: NDA, service agreement, Appendix A, Appendix B
3. Verify the order using the thumbnail preview
4. Merge into a single document
5. Add page numbers if needed
6. Compress the final file if it exceeds email attachment limits -- see how to reduce PDF file size for guidance
7. Send the single merged PDF to the client

Workflow 2: Extracting Receipts for Expense Reports

Situation: Your company's expense system requires individual PDF receipts. You have a 30-page bank statement PDF and need to extract five specific receipts.

Steps:

1. Open the split PDF tool
2. Upload the bank statement
3. Select the pages containing the five receipts (e.g., pages 3, 7, 12, 18, and 24)
4. Split into individual page PDFs
5. Rename each file with the expense description
6. Upload the individual receipt PDFs to the expense system

Workflow 3: Creating a Portfolio

Situation: You are a designer applying for a job. Your work samples are spread across multiple PDFs and image files.

Steps:

1. Convert any image files (JPEG, PNG) to PDF using the PDF converter
2. Create a cover page in your design tool and export as PDF
3. Open the merge PDF tool
4. Upload the cover page first, followed by work samples in your preferred order
5. Merge into a single portfolio PDF
6. Compress if the file is too large for email or upload platforms

Workflow 4: Distributing Individual Forms

Situation: You downloaded a government form packet that contains 15 different forms in a single PDF. You only need three of them.

Steps:

1. Open the extract pages from PDF tool
2. Upload the form packet
3. Browse thumbnails to identify the three forms you need
4. Select the relevant page ranges for each form
5. Extract and download each form as a separate PDF

Workflow 5: Book Chapter Management

Situation: You have a scanned book (300 pages) and need to split it into individual chapters for a study group where each member takes a different chapter.

Steps:

1. Note the page ranges for each chapter from the table of contents
2. Open the split PDF tool
3. Upload the scanned book
4. Define split points at each chapter boundary
5. Download the individual chapter PDFs
6. Distribute to study group members

PDF Tool Comparison

The following table compares the key PDF management tools available on ConvertIntoMP4 to help you choose the right one for your task.

Handling Large PDFs

File Size Considerations

Merging multiple large PDFs can produce very large output files. A few guidelines:

• Email attachment limits are typically 10-25 MB. If your merged PDF exceeds this, use the compress PDF tool or a file-sharing service.
• Scanned PDFs are large by nature because each page is a high-resolution image. A 100-page scanned document might be 200+ MB.
• Image-heavy documents (presentations, photo books, design portfolios) accumulate size quickly.

Compression After Merging

The most efficient approach is to merge first, then compress the result. Compressing the merged file allows the compression algorithm to optimize across all pages rather than each file individually. See how to reduce PDF file size for detailed compression strategies.

Performance Tips

When working with very large PDFs (500+ pages, 100+ MB):

• Upload over a stable connection. Large file uploads can fail on unstable networks.
• Be patient with processing. Large documents take longer to process than small ones.
• Split before other operations. If you only need a few pages from a large PDF, extract those pages first, then perform other operations (OCR, compression, signing) on the smaller file.

Preserving Document Quality

What Merging and Splitting Preserve

Well-implemented merge and split operations preserve:

• Text content and formatting -- fonts, sizes, colors, alignment
• Images -- embedded images at their original resolution
• Hyperlinks -- internal and external links
• Form fields -- fillable fields remain interactive
• Bookmarks -- table of contents and navigation bookmarks
• Annotations -- comments, highlights, and markup
• Page dimensions -- each page retains its original size and orientation

What Can Be Lost

Some elements may not survive merging or splitting perfectly:

• Cross-document links. If Document A has a hyperlink to "page 5" and this refers to a specific page within Document A, the link may break if that page's position changes in the merged output.
• Incremental page numbering. Printed page numbers (in headers or footers) from source documents will not automatically renumber in the merged output.
• Document-level JavaScript. PDFs with embedded JavaScript (rare) may not execute correctly after merging.
• Digital signatures. Cryptographic digital signatures are invalidated when the document is modified (which merging and splitting inherently do). Electronic signatures (visual representations) are preserved.

Automating PDF Operations

Batch Processing

If you regularly need to merge or split PDFs as part of a repeatable workflow, consider automating the process:

• API integration. ConvertIntoMP4 offers an API that supports programmatic merge, split, and conversion operations. This enables integration with document management systems, CRM platforms, and custom workflows.
• Scheduled processing. Set up automatic processing of documents that arrive in a specific folder or email inbox.
• Template-based splitting. Define reusable split configurations (e.g., "always split quarterly reports into monthly sections at pages 15, 30, and 45").

Command-Line Tools

For technical users, command-line tools like pdftk, qpdf, and Ghostscript provide powerful merge and split capabilities that can be scripted:

# Merge with pdftk
pdftk file1.pdf file2.pdf file3.pdf cat output merged.pdf

# Split into individual pages with pdftk
pdftk input.pdf burst output page_%02d.pdf

# Extract pages 5-10 with qpdf
qpdf input.pdf --pages . 5-10 -- output.pdf

These tools are particularly useful for processing large batches of documents or integrating PDF operations into automated pipelines.

Security When Merging and Splitting

Password-Protected PDFs

If any source PDF is password-protected, you will need to provide the password before it can be merged or split. The merge tool cannot combine a locked PDF without the decryption password.

Similarly, if you want the merged output to be password-protected, apply encryption to the final merged file as a separate step.

Sensitive Content

When splitting a document that contains both sensitive and non-sensitive sections, splitting is a simple way to create a shareable version without sensitive content. Extract only the non-sensitive pages and share that subset rather than the full document.

For more granular content removal (redacting specific text or images on a page), you would need a dedicated redaction tool rather than split/extract functionality.

Conclusion

Merging and splitting PDFs are foundational document management skills. Merging creates unified documents from separate files -- essential for contracts, portfolios, reports, and any situation where a single PDF is more practical than multiple files. Splitting breaks large documents into manageable pieces -- ideal for extracting specific content, distributing sections, or isolating forms from packets.

The merge PDF and split PDF tools on ConvertIntoMP4 handle both operations directly in the browser without software installation, file size limits, or watermarks. For page-level control, the organize PDF and extract pages from PDF tools provide visual interfaces for precise page management.

Combined with compression, OCR, signing, and format conversion, these tools form a complete PDF workflow that covers virtually any document management scenario. Start with the operation that matches your immediate need, and layer additional tools as your workflow requires.