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UUID Generator

Generate UUIDs v1-v7 with bulk generation. All processing happens locally in your browser.

About UUIDs

A UUID (Universally Unique Identifier) is a 128-bit number used to identify information in computer systems. UUIDs are standardized by RFC 4122 and RFC 9562.

UUID Versions

  • v1 (Timestamp): Based on timestamp and MAC address. May reveal when and where it was generated.
  • v3 (MD5 Hash): Deterministic, uses MD5 hash of namespace + name.
  • v4 (Random): Completely random. Most commonly used with no information leakage.
  • v5 (SHA-1 Hash): Deterministic, uses SHA-1 hash of namespace + name. Preferred over v3.
  • v6 (Sortable Timestamp): Like v1 but rearranged for lexicographic sorting. Great for databases.
  • v7 (Unix Timestamp): Uses Unix timestamp in milliseconds. Newest standard (RFC 9562), sortable and privacy-preserving.
  • Nil UUID: All zeros. Used as a special placeholder value.

UUID Structure

xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx

M = Version (1-7), N = Variant (8, 9, A, or B)

Collision Probability

UUID v4 has 122 random bits. To have a 50% probability of a collision, you would need to generate approximately 2.71 × 1018 UUIDs — that's roughly 1 billion per second for 85 years.