RAR Files
RAR5 vs RAR4: What Is the Difference?
RAR5 is the newer version of the [RAR file format](/rar-file-format), introduced to support larger dictionary sizes and stronger encryption. RAR4 is the older version, and it's still relevant because some tools don't understand RAR5 yet.
When WinRAR creates an archive, it asks which RAR format version to use: RAR5 or RAR4 (labeled RAR4 in the archive format options, sometimes just "RAR"). Both are variants of the same RAR file format, but they store data differently under the hood, and that affects compression, security, and which programs can open the result.
Key differences
| Feature | RAR5 | RAR4 |
|---|---|---|
| Maximum dictionary size | Much larger (up to 1 GB in modern WinRAR) | Smaller (up to 4 MB) |
| Encryption | AES-256 | AES-128 |
| Filename encryption | Included automatically when a password is set with "Encrypt file names" | Optional, but weaker implementation |
| File extension for split volumes | .part1.rar, .part2.rar, etc. | .rar, .r00, .r01, etc. |
| Compatibility with older extractors | Requires a reasonably current unarchiver | Opens in almost any RAR-capable tool, including very old ones |
| Recovery record format | Updated format | Older format |
A larger dictionary size generally lets RAR5 find more redundancy across a file, which can help compression on large files, though the practical gain depends heavily on the data itself. The bigger practical difference for most people is encryption and compatibility.
Encryption strength
RAR5 uses AES-256 by default for RAR encryption, while RAR4 uses AES-128. Both are strong in practice for typical use, but AES-256 has a larger key space. If you're creating a password-protected RAR file for anything sensitive, RAR5 is the safer default.
Compatibility: the real reason RAR4 still exists
RAR5 was introduced years after RAR4, so older extraction tools, some mobile apps, and certain embedded or legacy systems may not recognize RAR5 archives at all, or may only partially support them. If you know the recipient is using an older archive tool, or you're distributing files to an audience where you can't control the software they have, choosing the RAR4 format when creating the archive avoids that problem entirely.
This choice is made when creating an archive, not when extracting one — a good extractor like WinRAR or 7-Zip reads both formats automatically. See how to create a RAR file for where this option appears.
Frequently asked questions
Can WinRAR open RAR5 archives?
Yes, current versions of WinRAR fully support both RAR5 and RAR4. Compatibility issues mostly come up with older or third-party tools.
Does RAR5 compress better than RAR4?
It can, mainly due to the larger available dictionary size, but the difference depends on the type of data being compressed.
Is RAR4 less secure than RAR5?
RAR4 uses AES-128 encryption versus AES-256 in RAR5. Both are considered strong for typical use, but RAR5 has a larger key space.
How do I tell which format an archive uses?
Split RAR5 archives use `.part1.rar` naming, while split RAR4 archives use `.rar`, `.r00`, `.r01`. A single, unsplit archive's format isn't obvious from the extension alone; an extractor will tell you when it opens it.
Should I pick RAR5 by default?
Yes, unless you specifically know the people or systems you're sharing with can't read RAR5 archives.
Related guides
- What Is a RAR File?A RAR file (.rar) is a compressed archive that bundles one or more files together using RARLAB's proprietary compression format.
- The RAR File Format ExplainedRAR is a proprietary archive format with its own header structure, versioning, and optional features like solid compression and recovery records.
- What Is RAR Encryption?RAR encryption scrambles the contents of an archive using AES, unlockable only with the correct password. For the extraction-focused version of this topic, see [password-protected RAR files](/password-protected-rar-files).
- Password-Protected and Encrypted RAR ArchivesA password-protected RAR archive uses encryption to keep its contents unreadable without the correct password — there is no legitimate shortcut around one you don't know.
- How to Create a RAR FileOnly RARLAB's own tools can create a genuine RAR archive. Here's how to do it in WinRAR, and what to consider if you'd rather not use it.
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