.ARJ File Extension Reference
The .ARJ format is the compressed archive of Robert K. Jung, popular in the DOS era; modern 7-Zip and PeaZip still extract it. Files with the .ARJ extension are categorized under Archives and are widely utilized in modern computing environments for storing, rendering, and exchanging structured data. By verifying the header signature (60 EA) using forensic byte inspection tools, users can authenticate file integrity and rule out disguised executable payloads.
Quick Specification & Metadata
.ARJ
Archives
application/x-arj
Robert K. Jung
N/A
Proprietary / Patent Licensed
Binary Header Data
100 KB - 100 MB
Online .ARJ Viewer & Live Inspector
Open, inspect, zoom, and export .ARJ files directly in your web browser. 100% private in-memory processing.
Drop your .ARJ file here or browse
Inspect and preview any .ARJ file securely with zero server uploads.
What is a .ARJ File? (Technical Definition & Architecture)
The .ARJ format is the compressed archive of Robert K. Jung, popular in the DOS era; modern 7-Zip and PeaZip still extract it. Files with the .ARJ extension are categorized under Archives and are widely utilized in modern computing environments for storing, rendering, and exchanging structured data. By verifying the header signature (60 EA) using forensic byte inspection tools, users can authenticate file integrity and rule out disguised executable payloads.
Reduces raw disk footprint through dictionary and entropy symbol substitution.
Retains directory trees, UNIX file permissions, symlinks, and timestamps.
Protects archive contents with encryption and verifies transfer integrity.
ARJ Binary Structure & Header Specifications
The .ARJ format organizes data into validated sequential or hierarchical byte structures. Inspecting the header offset reveals the magic byte sequence 60 EA.
- File Signature (Magic Bytes): 60 EA
- MIME Content-Type: application/x-arj
- Payload Structure: Optimized data stream with metadata headers and checksum records.
- Safety Classification: Low Risk – Scan extracted files from archives downloaded from the internet Legacy ARJ archives sometimes carry old DOS executables Files ending in .ARJ should always be inspected for valid magic bytes to verify they match legitimate Archives specifications.
How to Open .ARJ Files on Windows, Mac & Android
- 1Primary Application: Double-click or open directly with 7-Zip.
- 2Alternative Software: Open using PeaZip.
- 3File Association: Right-click the file, select Open with > Choose another app, and check Always use this app.
- 1Native macOS Application: Open with 7-Zip.
- 2Quick Look Preview: Highlight the file in Finder and tap the Spacebar.
- 3Set Default App: Press Cmd + I, expand Open with, select your application, and click Change All.
- 1Compatible Mobile Apps: Download a dedicated viewer for .arj from the Google Play Store.
- 2Cloud Storage: Open through Google Drive, Dropbox, or OneDrive mobile apps.
- 3Online Browser Conversion: Use AnyFileX mobile browser tools to convert the file into universal PDF or image formats.
Convert .ARJ Files Online & Free
Convert your .ARJ files directly into standardized .ZIP format with high precision and zero privacy compromises.
Export .ARJ files to .PDF for universal cross-platform viewing, printing, and sharing.
.ARJ MIME Types & HTTP Server Headers
When serving .arj files over HTTP or configuring REST APIs, web servers must send the official IANA registered Content-Type headers:
| MIME Type Identifier | Standard Usage | File Extensions | Copy |
|---|---|---|---|
| application/x-arj | Standard official MIME type for .arj files | .arj |
# Nginx mime.types
types {
application/x-arj arj;
}
# Apache .htaccess
AddType application/x-arj .arj.ARJ Magic Bytes & Hex File Signatures
In digital forensics and file signature analysis, authentic .arj files begin with a standardized magic byte sequence at byte offset 0x00 to verify file integrity and prevent extension spoofing:
Offset 0x0060 EAARJArchives File Format.ARJ vs .ZIP (Detailed Format Comparison)
| Feature Metric | .ARJ | .ZIP | Advantage |
|---|---|---|---|
| Format Full Name | ARJ File Format | ZIP Compressed Archive | Tie / Equal |
| Category | Archives | Archives | Tie / Equal |
| MIME Content-Type | application/x-arj | application/zip | Tie / Equal |
| Binary Header (Magic Bytes) | 60 EA | 50 4B 03 04 (PK..) | Tie / Equal |
| Typical Storage Footprint | 100 KB - 100 MB | 1 MB – 5 GB | Tie / Equal |
| Universal Native Support | High / OS Standard | High / OS Standard | Tie / Equal |
.ARJ Compatibility Matrix
Supported natively or through 7-Zip
Supported natively or via PeaZip
Supported via open-source tools and command line utilities
Accessible through compatible mobile viewers or cloud previewers
Supported through dedicated mobile apps or cloud viewers
Accessible via web browser applications and Chrome extensions
Recommended Software for .ARJ
7-Zip Archive Utility
Igor Pavlov
WinRAR Archiver
win.rar GmbH / Eugene Roshal
Common Errors & Troubleshooting .ARJ Files
Security & Malware Risk Assessment
Can a .ARJ file carry viruses or malware?
Scan extracted files from archives downloaded from the internet Legacy ARJ archives sometimes carry old DOS executables Files ending in .ARJ should always be inspected for valid magic bytes to verify they match legitimate Archives specifications.
No active macro execution support
Safe to inspect with AnyFileX's browser sandbox
- •Verify file extension in OS File Explorer options ('Show known file extensions').
- •Verify magic bytes (60 EA) to ensure the file isn't a renamed executable.
- •Do not open .ARJ attachments received unexpectedly via email or instant messenger.
Frequently Asked Questions
Explore related information about .ARJ files
Related Extensions
Related Converters
Related Software
Repair & Comparisons
Popular Knowledge Base Guides
Browse Category Pages
Related Questions
Recently Viewed Extensions
Your recently inspected file extensions will appear here for rapid re-visitation.