How to Split Large Files into Multiple Parts in Windows

Moving large files between computers, uploading them to cloud storage, or sending them through email can be frustrating when you hit file size limits. The solution is simple: split your large file into smaller, manageable parts.

This guide shows you exactly how to split large files in Windows, whether you’re dealing with videos, backups, archives, or any other large data. You’ll learn multiple methods, from built-in Windows tools to specialized software, plus how to rejoin those files later.

Why You Need to Split Large Files

Before diving into the methods, let’s understand when file splitting becomes necessary:

Common scenarios:

• Email attachments limited to 25MB or less
• USB drives formatted as FAT32 (4GB file size limit)
• Cloud storage upload restrictions
• Slow internet connections that timeout on large uploads
• Sharing files across multiple storage devices
• Backing up data to DVDs or other limited-capacity media

When you split a file, you create multiple smaller pieces that can be transferred separately and reassembled on the destination computer.

Method 1: Using 7-Zip (Best Free Option)

7-Zip is a free, open-source compression tool that includes excellent file-splitting capabilities. This is the method I recommend for most users.

Installing 7-Zip

1. Visit the official 7-Zip website
2. Download the version matching your Windows architecture (64-bit or 32-bit)
3. Run the installer
4. Follow the installation prompts

Splitting Files with 7-Zip

Step-by-step process:

1. Right-click the large file you want to split
2. Hover over “7-Zip” in the context menu
3. Select “Add to archive”
4. In the “Add to Archive” window, you’ll see several options

Configuration settings:

• Archive format: Choose “zip” or “7z” (7z offers better compression)
• Compression level: Select based on your needs (Store = no compression, fastest)
• Split to volumes: This is where you specify the size of each part

Understanding Split Volume Sizes

In the “Split to volumes, bytes” dropdown, you’ll find preset options:

Size Option	Best For
10M	Email attachments
25M	Gmail attachment limit
100M	Standard web uploads
650M	CD capacity
700M	CD capacity
4092M	FAT32 maximum file size
Custom	Your specific needs

You can also type custom values:

• Use “M” for megabytes (example: 50M)
• Use “G” for gigabytes (example: 2G)
• Use “K” for kilobytes (example: 5000K)

Example: If you have a 10GB video file and want to split it into 2GB parts, type “2G” in the split volumes field.

5. Click “OK” to start the splitting process
6. Wait for 7-Zip to create the parts

What You Get After Splitting

7-Zip creates multiple files with extensions like:

• filename.7z.001
• filename.7z.002
• filename.7z.003

Each file represents one part of your original large file.

Rejoining Files Split with 7-Zip

The recombination process is straightforward:

1. Place all split parts in the same folder
2. Right-click the first part (the .001 file)
3. Select “7-Zip” then “Extract Here”
4. 7-Zip automatically detects and combines all parts
5. Your original file appears in the folder

Important: All parts must be present and in the same location, or extraction will fail.

Method 2: Using WinRAR

WinRAR is another popular compression tool with file-splitting capabilities. While it’s not free (after trial), many users already have it installed.

Splitting Files with WinRAR

1. Right-click your large file
2. Select “Add to archive”
3. In the archive name field, specify your desired name
4. Under “Split to volumes, bytes”, enter your preferred size
5. Click “OK”

WinRAR creates parts with extensions:

• filename.part1.rar
• filename.part2.rar
• filename.part3.rar

Extracting WinRAR Split Archives

1. Keep all parts together in one folder
2. Right-click the first part
3. Choose “Extract Here” or “Extract to”
4. WinRAR handles the rest automatically

Method 3: Using Windows PowerShell (No Additional Software)

For users who prefer built-in tools, PowerShell offers file-splitting without third-party software.

Splitting Files with PowerShell

Basic syntax:

$file = "C:\path\to\your\largefile.zip"
$outputPath = "C:\path\to\output\folder\"
$chunkSize = 100MB

$stream = [System.IO.File]::OpenRead($file)
$chunkNum = 0
$buffer = New-Object byte[] $chunkSize

while ($bytesRead = $stream.Read($buffer, 0, $chunkSize)) {
    $chunkNum++
    $chunkFileName = "$outputPath\largefile.zip.part$chunkNum"
    $chunkFile = [System.IO.File]::Create($chunkFileName)
    $chunkFile.Write($buffer, 0, $bytesRead)
    $chunkFile.Close()
}
$stream.Close()

To use this:

1. Open PowerShell as Administrator
2. Modify the paths and chunk size to match your needs
3. Copy and paste the code
4. Press Enter to execute

Rejoining PowerShell Split Files

$outputFile = "C:\path\to\rejoined\largefile.zip"
$inputPath = "C:\path\to\parts\"

$parts = Get-ChildItem "$inputPath\largefile.zip.part*" | Sort-Object Name

$output = [System.IO.File]::Create($outputFile)

foreach ($part in $parts) {
    $bytes = [System.IO.File]::ReadAllBytes($part.FullName)
    $output.Write($bytes, 0, $bytes.Length)
}
$output.Close()

This method requires more technical knowledge but offers complete control without installing software.

Method 4: Using File Splitter Programs

Several specialized programs exist solely for splitting files. These offer user-friendly interfaces specifically designed for this task.

Popular File Splitter Tools

HJSplit:

• Completely free
• Simple interface
• No compression (splits raw files)
• Small download size

GSplit:

• Free for personal use
• Can create self-joining executables
• Batch splitting capability
• Checksum verification

File Splitter and Joiner:

• Available on Microsoft Store
• Modern interface
• Easy for beginners

When to Use Dedicated Splitters

Choose dedicated splitters when:

• You don’t need compression
• You want the fastest possible splitting
• You split files regularly
• You need simple, one-click operation

Method 5: Command Prompt (Advanced Users)

Windows Command Prompt can also split files without additional software.

Using FSUTIL (File System Utility)

This method creates a sparse file but doesn’t truly split. For actual splitting via CMD:

certutil -split -split size_in_bytes input_file output_prefix

However, this is limited and less reliable than other methods.

Choosing the Right Method for Your Needs

Method	Best For	Pros	Cons
7-Zip	General users	Free, compression, reliable	Requires installation
WinRAR	Existing WinRAR users	Familiar interface	Not free (trial available)
PowerShell	Tech-savvy users	No installation needed	Complex commands
Dedicated splitters	Frequent splitting	Simple, fast	Limited additional features

Tips for Successfully Splitting and Transferring Files

Before splitting:

• Verify you have enough disk space (at least 2x the original file size)
• Close the file you’re splitting (ensure no programs are using it)
• Choose split sizes appropriate for your destination

During transfer:

• Transfer all parts, not just some
• Maintain original filenames (don’t rename parts)
• Verify file integrity after transfer using checksums if possible

After rejoining:

• Compare file sizes (original vs. rejoined) to verify completeness
• Test the rejoined file before deleting split parts
• Keep backups until you confirm everything works

Common Problems and Solutions

Problem: “Cannot find part file”

Solution: Ensure all parts are in the same folder with sequential numbering intact.

Problem: Extraction fails partway through

Solution: One or more parts may be corrupted. Re-transfer those specific parts and try again.

Problem: Wrong split size chosen

Solution: Delete the parts and re-split with the correct size. There’s no way to adjust after splitting.

Problem: File won’t open after rejoining

Solution:

• Verify all parts were transferred completely
• Check that the rejoined file size matches the original
• Ensure no parts are missing from the sequence

File Compression vs. Splitting

It’s important to distinguish between these two operations:

Compression:

• Reduces file size
• Single output file (usually)
• Requires decompression to access content
• Takes more processing time

Splitting:

• Maintains original file size
• Multiple output files
• May or may not include compression
• Faster operation

7-Zip and WinRAR combine both operations, allowing you to compress AND split simultaneously. This is often the best approach as you get smaller files that are also split into manageable parts.

Security Considerations When Splitting Files

When splitting sensitive files:

1. Use encryption: Both 7-Zip and WinRAR offer password protection with AES-256 encryption
2. Secure transfer: Use encrypted connections (SFTP, HTTPS) when uploading split files
3. Delete securely: Use file shredding tools to remove original and split files after transfer
4. Verify recipients: Ensure all parts reach only intended recipients

Automation for Regular File Splitting

If you regularly split files, consider automating the process:

Creating batch files:

For 7-Zip, create a .bat file with:

"C:\Program Files\7-Zip\7z.exe" a -v100m "output.7z" "C:\path\to\input\file.ext"

Save this as “split-file.bat” and run it whenever needed.

Scheduled tasks:

Use Windows Task Scheduler to run splitting operations automatically at specific times or intervals.

Best Practices from Real-World Usage

After splitting thousands of files, these practices ensure smooth operations:

1. Document your splits: Keep a text file noting original filenames, split sizes, and part counts
2. Use descriptive names: Instead of “file.zip”, use “ProjectBackup_2024_10MB_parts.zip”
3. Test small first: Before splitting a 100GB file, test your method on a smaller file
4. Maintain checksums: Generate MD5 or SHA256 hashes before and after to verify integrity
5. Keep one complete copy: Don’t delete your original until you’ve verified the splits work

According to Microsoft’s documentation on file management, maintaining file integrity during operations like splitting is critical for data preservation.

Conclusion

Splitting large files in Windows is straightforward once you know the right tools and methods. For most users, 7-Zip offers the best combination of features, reliability, and cost (free). It compresses while splitting, includes strong encryption, and works across all Windows versions.

The key points to remember:

• Choose appropriate split sizes for your destination
• Keep all parts together when transferring
• Verify successful recombination before deleting originals
• Use compression alongside splitting for maximum efficiency

Whether you’re sending large videos, backing up data, or working around file size restrictions, these methods give you complete control over managing large files in Windows.

Frequently Asked Questions

Can I split any type of file?

Yes, file splitting works with any file type including videos, images, documents, executables, and archives. The file type doesn’t matter as splitting operates at the binary level, dividing the raw data into chunks.

Do I need the same program to rejoin files?

Generally, yes. Files split with 7-Zip should be rejoined with 7-Zip, and WinRAR splits need WinRAR for extraction. However, 7-Zip can sometimes extract RAR archives. Dedicated splitters usually create parts that only their own program can rejoin.

Will splitting affect file quality?

No, splitting is a lossless operation. When properly rejoined, the file is bit-for-bit identical to the original. This applies to videos, images, and all other file types. Quality loss only occurs with lossy compression, which is a different process.

How many parts can I split a file into?

There’s no practical limit. You could split a 100GB file into 10,000 parts of 10MB each if needed. However, managing hundreds or thousands of parts becomes impractical. Aim for 5 to 20 parts for easier handling.

What happens if one part gets corrupted?

The entire file cannot be reconstructed properly. If you discover corruption, you’ll need to re-transfer or recreate only the corrupted part. This is why verifying file integrity (using checksums) after transfer is important. Some programs like WinRAR include recovery records that can repair minor corruption.