UUID v3 Generator

Generate deterministic UUID v3 values

UUID version 3 creates a name-based identifier from a namespace UUID and a name using MD5. The same namespace and exact input name always produce the same UUID, making UUIDv3 suitable for repeatable mappings rather than random identifiers.

Choose one of the standard DNS, URL, OID, or X.500 namespaces, then enter the name exactly as the surrounding system defines it.

How to generate UUID v3

1. Select the namespace that describes the input name.
2. Enter the complete, case-sensitive name.
3. Choose conventional hyphenated output unless another format is required.
4. Generate and verify the result against the same namespace rules used by the receiving system.

For the DNS namespace, name example.com produces 9073926b-929f-31c2-abc9-fad77ae3e8eb.

Namespace and name normalization

RFC 9562 defines standard namespace UUIDs and the UUIDv3 construction. The name is a sequence of bytes; differences in capitalization, whitespace, URL normalization, or Unicode representation can produce another identifier.

UUIDv3 uses MD5 as part of a standardized identifier mapping, not for password storage or cryptographic authentication. Use UUID v5 when the interoperating format specifies the SHA-1 name-based version.

UUID v3 FAQ

Why does the same text produce different UUIDs?

The selected namespace may differ, or the input may not be byte-for-byte identical after normalization and encoding.

Can the original name be recovered from UUID v3?

The UUID does not embed the original name. However, it should not be treated as a secret or as protection for a guessable name.

When should I use UUID v4 instead?

Use UUID v4 when each new identifier should be random rather than deterministically derived from a namespace and name.