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UUID v3 Generator (MD5)

Turn names into stable version 3 UUIDs: the same namespace and name always produce the same identifier.

Processed locally in your browser

Options

Used when the namespace is “Custom”.

The same namespace and name always give the same UUID. Blank lines are skipped.0 chars · 0 lines
The result will appear here.

What is UUID v3 Generator (MD5)?

A version 3 UUID is not random. It is the MD5 hash of the namespace UUID (16 bytes) followed by the name (UTF-8), with the version nibble set to 3 and the variant bits set to 10. RFC 9562 defines four standard namespaces, DNS, URL, OID and X.500, and you can supply your own.

Enter one name per line and every line becomes one UUID. The tool also shows the raw MD5 digest and how the version and variant bits change it for the first name, so you can reproduce the value in any language. MD5 is kept only for compatibility; version 5 uses SHA-1 and is the recommended choice for new designs.

How does it work?

  1. Type or paste one name per line, for example domain names or product codes.
  2. Choose the namespace (DNS, URL, OID, X.500) or paste your own namespace UUID.
  3. Select the output: UUIDs only, UUID and name, CSV or a JSON object, plus uppercase or hyphen options.
  4. Copy the result and check the breakdown panel to see the MD5 digest behind the first UUID.

Common use cases

  • Matching identifiers already generated by a system that used v3, such as Java’s UUID.nameUUIDFromBytes-style libraries.
  • Deriving a stable ID for an existing record from its natural key, so imports are idempotent.
  • Explaining to a team why the same input always gives the same UUID.
  • Cross-checking your own MD5-based UUID code against a reference implementation.

Examples

Try this input in the tool above:

Input
python.org
example.com
Output
6fa459ea-ee8a-3ca4-894e-db77e160355e
9073926b-929f-31c2-abc9-fad77ae3e8eb

Privacy

UUID v3 Generator (MD5) runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

A v3 UUID is derived from a name, so anyone who guesses the name and namespace can recompute it; it is not a secret. MD5 is weak against collisions, so use v5 unless you need v3 for compatibility.

Frequently asked questions

What is the difference between v3 and v5?

Both hash a namespace and a name. Version 3 uses MD5 and version 5 uses SHA-1, so the same input gives different UUIDs. Only version 3 is meant for compatibility with existing MD5-based data.

Which namespace should I use?

Use DNS for domain names, URL for full URLs and OID or X.500 for those identifier types. For anything else, generate one UUID once and reuse it as your own namespace.

Does Java’s nameUUIDFromBytes match this?

Java’s method hashes only the bytes you pass, without a namespace prefix. To match it, you would have to hash the name alone; this tool follows the RFC and prepends the namespace.

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