UUID v5 Generator

Generate deterministic UUID v5 identifiers from a namespace UUID and a name string using SHA-1 hashing per RFC 4122.

Use the UUID v5 Generator

Any UTF-8 string — a domain, URL, path, or arbitrary identifier.

Generated UUID v5

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Enter a name and click Generate.

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Summary

UUID v5 produces a deterministic, namespace-scoped identifier by hashing a namespace UUID together with a name string using SHA-1 (RFC 4122 §4.3). Unlike UUID v4, the same namespace + name pair always yields the same UUID, making v5 ideal for reproducible resource identifiers. This tool runs entirely in your browser — no data is sent to any server.

How it works

  1. Choose a standard namespace (DNS, URL, OID, X.500) or enter a custom namespace UUID.
  2. Type the name string you want to hash into the namespace.
  3. The tool concatenates the namespace UUID bytes and the name UTF-8 bytes, then computes SHA-1.
  4. The first 16 bytes of the SHA-1 digest are taken and the version (5) and variant bits are set.
  5. The resulting 128-bit value is formatted as a standard 8-4-4-4-12 UUID string.
  6. Click "Copy UUID" to copy the result to your clipboard.

Use cases

  • Generate stable IDs for DNS hostnames that are always the same given the same input.
  • Create reproducible UUIDs for database seed data across environments.
  • Assign deterministic identifiers to REST resources without storing a mapping table.
  • Namespace URL identifiers for RDF/Linked Data graphs.
  • Generate test fixture IDs that remain stable across test runs.
  • Build content-addressable references for documents or assets.

Frequently Asked Questions

Last updated: 2026-05-28 · Reviewed by Nham Vu