ARJ to 7Z Converter

Convert obsolete ARJ archives to efficient 7Z online free

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Modern Compression

Replace ARJ's dated compression with 7Z's LZMA2 algorithm — expect dramatically smaller archives from the same set of files.

No Tools Required

Finding working ARJ software is a challenge. Convertio.tools handles extraction and repacking in the cloud — no local tools needed at all.

Automatic Cleanup

All uploaded ARJ files are deleted right after conversion. The resulting 7Z files are removed from our servers within 24 hours.

How to convert ARJ to 7Z

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose 7z or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your 7z file right afterwards

About formats

ARJ (Archived by Robert Jung) is a compressed archive format created by Robert K. Jung in 1991 for MS-DOS, which became one of the most popular archiving tools during the early 1990s. The format uses a proprietary compression algorithm based on LZ77 sliding window techniques combined with Huffman coding, offering competitive compression ratios that rivaled or exceeded other DOS-era archivers. ARJ archives support multi-volume spanning across floppy disks, a critical feature in an era when distributing software often meant shipping multiple 1.44 MB diskettes. The format also provides password protection, file attribute and timestamp preservation, archive integrity verification through CRC-32 checksums, and the ability to create self-extracting executables. ARJ saw widespread adoption on bulletin board systems and in corporate environments during the DOS and early Windows period, valued for its balance of compression ratio, speed, and feature set. One advantage was excellent multi-volume support — ARJ handled spanning across floppy disks more reliably than many competitors, making it a preferred choice for software distribution via physical media. The self-extracting archive capability provided another practical strength, enabling recipients to unpack files without needing the ARJ utility installed. While ARJ's usage declined sharply with the rise of ZIP, RAR, and 7Z as internet-based distribution replaced floppy disks, the format remains recognized by modern archivers like 7-Zip for extracting legacy archives.
Developer: Robert Jung
Initial release: 1991
7Z is the native archive format of 7-Zip, an open-source file archiver created by Igor Pavlov in 1999. The format uses an open, modular architecture that supports multiple compression algorithms — LZMA and LZMA2 (the defaults), PPMd for text-heavy data, BWT, and Deflate — selectable per file within the same archive. LZMA typically achieves 30-70% better compression ratios than Deflate-based ZIP files on comparable data, making 7Z one of the most space-efficient general-purpose archive formats available. The container structure stores files with full directory hierarchy, timestamps, and attributes, while supporting solid compression (treating multiple files as a continuous data stream) for additional ratio gains on archives with many similar files. Encryption uses AES-256 with key derivation based on iterative SHA-256 hashing, and both file contents and filenames can be encrypted. One advantage is superior compression density — 7Z consistently produces smaller archives than ZIP or RAR on most data types, valuable when minimizing storage or bandwidth matters. The open architecture is another strength: the format specification and 7-Zip source code are publicly available under the GNU LGPL, enabling any developer to implement 7Z support without licensing constraints. Cross-platform tools supporting 7Z exist for Windows, macOS, Linux, and mobile platforms, and the format has gained widespread recognition as the preferred choice when maximum compression is the priority.
Developer: Igor Pavlov
Initial release: 1999

Frequently Asked Questions

Why upgrade from ARJ to 7Z?

7Z uses modern LZMA2 compression that is vastly more efficient than ARJ's algorithm, plus it supports AES-256 encryption for added security.

What opens 7Z files?

7-Zip is free and handles 7Z natively. PeaZip, WinRAR, and Keka (macOS) are other popular options for working with 7Z archives.

Is ARJ still supported by modern archivers?

Very few tools support ARJ today — even 7-Zip only reads ARJ. Converting to 7Z ensures your files remain accessible going forward.

Does converting to 7Z compress files better?

In almost every case, yes. 7Z achieves significantly smaller archive sizes compared to the compression algorithm ARJ used in the 1990s.

Can I convert multi-volume ARJ archives?

Upload the main ARJ file to convertio.tools. For best results with multi-volume archives, merge them into a single file before uploading.

ARJ to 7Z Quality Rating

3.8 (6 votes)
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