UtilMill

UUID Generator

Generate cryptographically random version 4 UUIDs — one at a time or in bulk — and copy them with one click.

Frequently asked questions

What is a version 4 UUID?

A 128-bit identifier where 122 bits are random, formatted as 36 characters (8-4-4-4-12). The 4 in the third group marks the version; the variant bits appear at the start of the fourth group.

Can two UUIDs collide?

In theory yes, in practice no: with 122 random bits you would need to generate about 2.7 quintillion UUIDs to reach a 50% chance of a single collision.

Are these UUIDs secure?

They are generated with the browser's crypto API, which uses a cryptographically secure random source. Still, UUIDs are identifiers, not secrets — do not use them as passwords or tokens.

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