RAR4 vs RAR5: What Is the Difference?
RAR4 and RAR5 are two generations of the RAR archive format. Both use the .rar extension, but they are structured differently inside, so a tool that reads one may fail on the other. This guide explains the real differences, how to tell which one you have, and what to do when an app says your RAR is “unsupported”.
Updated 2026-10-13 · Written and tested by the UnpackNest editorial team (TECCONET)
Step by step: check whether your file is RAR4 or RAR5
- Open the RAR tool and choose the file.
- Read the status line and the archive panel. Both name the detected generation, for example "RAR4".
- If the tool says the file is not a RAR, it may be a renamed ZIP or 7z; open it with the matching tool.
- On a computer, you can also check the first bytes: RAR4 starts with
Rar!followed by bytes 1A 07 00, RAR5 with 1A 07 01 00.
A short history
The RAR format has been developed by Eugene Roshal and later by win.rar GmbH since the early 1990s. The version most people call RAR4 (technically the RAR 2.9/3.x archive format) was the standard throughout the 2000s and early 2010s. In 2013, WinRAR 5.0 introduced the RAR5 format, a substantial redesign. WinRAR still lets you choose either format when creating an archive, so both are found in the wild, and RAR5 is the default in current versions.
The key differences at a glance
| Feature | RAR4 | RAR5 |
|---|---|---|
| File signature (first bytes) | 52 61 72 21 1A 07 00 | 52 61 72 21 1A 07 01 00 |
| Maximum dictionary size | 4 MB | Up to 1 GB (more in recent WinRAR) |
| Encryption | AES-128 | AES-256 with PBKDF2 key derivation |
| Checksums | CRC32 | CRC32 or BLAKE2sp |
| Recovery records | Basic | Improved, Reed–Solomon based, tolerant of more damage |
| File names | Limited Unicode handling | Full UTF-8 |
| Support in older tools | Very wide | Needs a tool updated after 2013 |
What these differences mean in practice
Compression
A larger dictionary lets the compressor find repeated data across a bigger window. For large collections of similar files (game assets, logs, source code), RAR5 with a large dictionary can produce a noticeably smaller archive. For a single photo or video, the difference is negligible because the data is already compressed.
The flip side is memory: decompressing an archive made with a 1 GB dictionary needs roughly that much memory. That is one reason a phone browser may refuse a RAR5 archive that a desktop handles easily.
Security
RAR4 uses AES-128 encryption. RAR5 uses AES-256 and a much slower password-derivation function, which makes brute-force password guessing far harder. If you are creating an encrypted archive today, RAR5 is the better choice, but a strong password matters more than the format.
Integrity and repair
Both formats store checksums so tools can detect damage. RAR5 can optionally use BLAKE2sp, a stronger cryptographic hash, and its recovery records can repair more damage. Recovery records only exist if the creator added them; most archives you download do not have them.
How to tell whether your archive is RAR4 or RAR5
The quick way
Open the archive in the UnpackNest RAR tool. It reads the first bytes of the file locally and reports the detected generation before extracting anything.
Using WinRAR
Open the archive and choose Info (or press Alt+I). The archive format is shown as “RAR4” or “RAR5”.
Using a hex viewer
Look at the first eight bytes. Rar! followed by 1A 07 00 is RAR4; 1A 07 01 00 is RAR5. On Linux or macOS you can run xxd -l 8 file.rar in a terminal.
Rar! at all, the file is not a RAR archive, whatever its extension says. It may be a ZIP, 7z or an incomplete download.“Unsupported archive”: what to do
- Identify the generation with one of the methods above.
- If it is RAR5 and your tool is old, update the tool or use a current one. Many mobile apps and old versions of desktop software only support RAR4.
- If the tool supports RAR5 but still fails, the issue is probably something else: encryption, a split archive, or a damaged download. Our RAR troubleshooting checklist walks through these causes.
- If the dictionary is very large, try a computer with more memory.
Other RAR5 changes worth knowing
Better handling of file names and metadata
RAR5 stores file names as UTF-8, so names in Arabic, Chinese, Cyrillic or with emoji survive the trip between computers with different language settings. Older RAR4 archives created on a system with a non-English code page sometimes show garbled names when opened elsewhere. If you see names made of random symbols, that is usually an encoding issue in an older archive, not damage to the data itself.
RAR5 can also store high-precision timestamps and, optionally, omit them for privacy. It handles NTFS file attributes, symbolic links and hard links more consistently, which matters for backups but less for everyday downloads.
Quick open information
RAR5 can store a copy of the file list near the end of the archive so tools can show the contents quickly without scanning the whole file. For large archives on slow drives, this makes listing noticeably faster.
Removed features
RAR5 dropped some older features such as authenticity verification (“AV”) signatures and the old comment format. If you rely on very old workflows that used those features, keep archives in RAR4.
A worked example
Suppose you download project-assets.rar (2.4 GB) and an older Android app says “unsupported format”, while the file opens fine on a laptop. Checking the first bytes shows 52 61 72 21 1A 07 01 00, so it is RAR5. WinRAR’s Info panel shows a 256 MB dictionary. The phone app only understands RAR4, and even a RAR5-capable phone tool would need about 256 MB of free memory to decompress it. The practical fix is to extract on the laptop, or to ask the sender to create the archive with a smaller dictionary or as a ZIP when it is meant for phones.
Which tools support which format?
- WinRAR 5.0 and later: both, and it can create both.
- 7-Zip: both for extraction since version 15.06.
- The Unarchiver (macOS): both in current versions.
- Windows 11 File Explorer: recent builds read RAR through the libarchive library; complex features such as encryption or multi-volume archives may not work.
- UnpackNest: detects both RAR4 and RAR5 in the browser. Encrypted entries and multi-volume sets are not currently extracted.
Should you create RAR4 or RAR5 archives?
If you create archives with WinRAR, choose RAR5 unless you know the recipient uses very old software. If you want maximum compatibility, ZIP is still the format almost every device opens without extra software. If you want strong open-source compression, 7z is a good alternative.
Checklist for senders
If you create RAR archives for other people, a few choices prevent most support questions. Use RAR5 for anything sensitive, and pick a strong, unique password shared through a different channel from the archive itself. Keep the dictionary moderate (32–128 MB) when recipients may use phones. Add a small recovery record (around 3%) to large archives that travel over unreliable links. Publish a SHA-256 checksum next to the download. And if you are not sure what the recipient uses, send a ZIP instead: it is the one archive format that almost every device opens out of the box.
Frequently asked questions
Can I convert RAR5 to RAR4?
Only by extracting and recompressing with WinRAR in RAR4 mode. There is no direct conversion, and you lose RAR5 features such as AES-256.
Is RAR5 slower to open?
Not noticeably for ordinary archives. Archives made with a very large dictionary need more memory, which can make them slower or impossible on low-memory devices.
Does the extension tell me anything?
No. Both use .rar. Split archives may use .part1.rar or the older .r00, .r01 naming, which is common for RAR4.
Why does my phone open some RAR files but not others?
Usually because the app only supports RAR4, or because the RAR5 archive needs more memory than the phone allows.
Tools for this task
- Open and extract RAR files in your browserRAR4 and RAR5, read on your device.
- Open 7z files and split .7z.001 archives onlineLZMA/LZMA2, AES-256, multi-volume.