UUID v5 Generator

A UUID v5 is a 128-bit identifier made by concatenating a namespace UUID and a name string, hashing them with SHA-1, and overwriting some bits of the result with version (5) and variant information. Because it's a computed value rather than a random one, the same namespace and name always produce the same UUID, no matter where or when it's computed.

Pick based on what kind of name you're hashing: DNS for a domain name, URL for a URL, OID for an ISO object identifier, or X.500 for an X.500 distinguished name. This tool provides the four standard namespace UUIDs defined in RFC 4122 — or click Randomize to generate a custom namespace, or type your own.

The computation is identical; only the hash algorithm differs. v3 uses MD5, which was cryptographically broken long ago, so RFC 4122 recommends SHA-1-based v5 for new implementations. SHA-1 is also no longer recommended for security purposes, but it's fine for name-based unique identifiers.

The `urn:uuid:` prefixed form is used when a UUID needs to be handled as a URI/URN, such as in XML namespaces, RDF, or some API specs. The underlying value is identical — only an identifying prefix is added.

No. Every computation happens on the spot in your browser — the namespace or name you enter is never sent to or stored on a server.