UUID Generator

Generate UUIDs in bulk — v4 (random), v7 (time-ordered, RFC 9562), v1 (timestamp), or v3/v5 (namespace-hashed). Inspect any UUID to see its version, variant, and embedded timestamp. 100% client-side.

Version Count Format

Standard No hyphens {Braced}

urn:uuid Base64 Hex only

Uppercase

Output

Click Generate to create UUIDs.

UUID

Byte layout

Which version should I use?

v4 Random: Default choice for new systems. 122 bits of entropy — effectively never collides. Not sortable.
v7 Time-ordered: Newer standard (RFC 9562, 2024). First 48 bits are Unix ms → sorts chronologically. Better for DB primary keys due to locality of inserts.
v1 Time + node: Legacy. Traditionally used the MAC address; browser version uses a random node. Embeds a 60-bit timestamp (100 ns since 1582).
v3 / v5: Deterministic — same namespace+name always produces the same UUID. v3 uses MD5, v5 uses SHA-1. Useful for generating a stable ID from external references.