Dummy RAR File Generator
Every dummy RAR file is a RAR5 archive that passes UnRAR and 7-Zip tests, from 512 Bytes to 1 GB.
Sample RAR files, ready to download:
One click, exact size (1 KB = 1,024 bytes), default options, built in your browser.
A dummy RAR file is a standard RAR5 archive made for testing, and it passes UnRAR and 7-Zip integrity tests. Download one free at the exact size you need, from 512 Bytes to 1 GB. It is built in your browser and bsdtar lists it too, so you can test upload validation, extraction and scanning for RAR files without hunting for a real archive.
How we check it: every generated file must be exactly the size you set and pass our own RAR5 parser (CRCs), UnRAR (WebAssembly build) and 7-Zip 24.09; the last run on 21 October 2026 passed 155 of 155 runs across 17 formats (how the files are made and checked).
Download a dummy RAR file by size
Each page below has a ready-made RAR test file, its exact byte count and the limits it is closest to.
What is inside a dummy RAR file
The archive uses the current RAR5 format with a minimal, predictable layout (how we build and check these files):
- The RAR5 signature (Rar! followed by 1A 07 01 00), a main archive header and an end-of-archive header, each with the CRC32 checksum that RAR tools verify.
- Two entries: README.txt, which explains what the file is, and archive_payload.dat, which holds zero bytes and carries almost all of the size.
- Entries use the store method (no compression), so the archive size equals the size you asked for and extraction is quick.
- A single volume that is not solid and not encrypted. Every entry has a CRC32 checksum, so "test archive" commands confirm the data is intact.
What a dummy RAR file is used for
Upload validation for RAR
Check that your upload handler accepts or rejects .rar files deliberately, whether the browser reports application/vnd.rar, application/x-rar-compressed or application/octet-stream.
Extraction support
Confirm your backend can open RAR5, not only ZIP. Many libraries and older tools only read RAR4, or no RAR at all.
Antivirus and DLP scanning
Make sure scanners unpack RAR archives and report on the contents instead of skipping a format they cannot open.
Size limits and transfer
Test upload caps, email attachment limits and storage quotas with a RAR at the exact byte count you need.
How to validate RAR uploads
Do not trust the extension or the browser-supplied MIME type alone. Read the first bytes: RAR5 starts with 52 61 72 21 1A 07 01 00 and the older RAR4 format with 52 61 72 21 1A 07 00. Reject files that claim to be .rar but do not start with either signature. A ZIP-based file such as a dummy Excel file starts with 50 4B instead, so the same check also tells RAR and Office uploads apart.
If you extract archives server-side, use a library that supports RAR5 and limit the total extracted size, the number of entries and the path of each entry so names such as ../ cannot escape the target folder.
Sample RAR file sizes and upload limits
The sizes above sit near common limits: 1 MB for the default nginx body limit, 10 MB for API Gateway and the default Exchange attachment limit, and 100 MB for Cloudflare Free and Pro plans. To test your own limit exactly, set the unit to B and generate one byte under, at and over it. If the same form also takes documents, run the three sizes with a dummy PDF file too. The table below lists the limits a dummy RAR can reach.
| Limit | Size | Notes |
|---|---|---|
| nginx client_max_body_size (default) | 1 MB 1,048,576 B | Requests with a larger body get HTTP 413. |
| PHP upload_max_filesize (default) | 2 MB 2,097,152 B | Also capped by post_max_size, so raise both. |
| AWS Lambda synchronous invocation payload | 6 MB 6,291,456 B | Applies to request and response. |
| Amazon API Gateway REST API payload | 10 MB 10,485,760 B | Hard quota for REST APIs. |
| Outlook default attachment limit (Exchange accounts) | 10 MB 10,485,760 B | Administrators can change it. |
| Outlook attachment limit (internet accounts) | 20 MB 20,971,520 B | Per Microsoft Outlook guidance. |
| Gmail message size limit | 25 MB 26,214,400 B | Attachments grow about a third when encoded, so a 20 MB file can already be too big. |
| Cloudflare proxy request body (Free and Pro plans) | 100 MB 104,857,600 B | Larger requests return HTTP 413. |
RAR vs ZIP for testing
ZIP support is nearly universal, while RAR support varies between libraries, operating systems and scanners. If your product accepts both, test both: a flow that works with a dummy ZIP file can still fail on RAR. Use the ZIP page for the ZIP half of the test.
RAR file details
- Extension
- RAR .rar
- MIME type
- application/vnd.rar
- Smallest size
- 512 Bytes
- Largest size
- 1 GB
- Contents
- Valid RAR5 archive (store method, no compression) with a README and a zero-filled payload file
RAR is a registered trademark of Alexander Roshal.
Dummy RAR file FAQ
Is the dummy RAR file a real archive?
Yes. It is a valid RAR5 archive with correct headers and CRC32 checksums. In our checks, the official UnRAR lists, tests and extracts it and 7-Zip tests it without errors, and bsdtar (libarchive) lists it.
Which programs can open it?
Any tool that reads RAR5. We check with UnRAR, 7-Zip and bsdtar (see the answer above for what each one does). Very old tools that only understand the RAR4 format cannot open RAR5 archives.
Is the RAR compressed?
No. It uses the RAR store method, so the file is exactly the size you chose and extracts to about the same size. It is also a single volume and not encrypted. Compression is not needed for size, upload and extraction tests.
What is the MIME type of a RAR file?
The registered type is application/vnd.rar. The older alias application/x-rar-compressed is deprecated but still seen, and browsers often send application/octet-stream, so upload handlers should check the file signature too.
How big can a dummy RAR file be?
From 512 Bytes up to 1 GB, at the exact byte count you choose. Large archives are assembled in chunks in your browser; very large ones still depend on your browser and free disk space.
Do I need WinRAR to create it?
No. The archive is written in your browser from the published RAR5 format description and never uploaded. You only need a RAR-capable tool if you want to open it.