UUID Generator
Free UUID generator. Create version 1, 4, or 7 UUIDs (one or many at a time), plus the nil and max UUIDs, using cryptographically secure randomness.
Frequently asked questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value, almost always written as 32 hex digits in five hyphen-separated groups (e.g. 123e4567-e89b-12d3-a456-426614174000). It's designed so that independently generated UUIDs are, for all practical purposes, guaranteed not to collide — even across different systems that never communicate with each other.
What is the difference between UUID v1, v4, and v7?
Version 4 is almost entirely random — the most common choice, with no information about when or where it was created. Version 1 encodes a timestamp plus a (randomized, in a browser) node identifier, making it time-based but not sortable as plain text. Version 7 is the newest type: it also encodes a timestamp, but places it at the front of the value, so v7 UUIDs sort chronologically as plain strings or bytes — useful as database primary keys, where sortable IDs keep indexes efficient.
Is this tool's randomness actually secure?
Yes — UUID v4 and the random portions of v1/v7 all come from the Web Crypto API's crypto.getRandomValues() (the browser's cryptographically secure random number generator), not Math.random(), which is not suitable for anything that needs real unpredictability.
What are the nil and max UUIDs?
The nil UUID (all zeros: 00000000-0000-0000-0000-000000000000) is a special reserved value meaning "no UUID" or an unset/placeholder value. The max UUID (all ones: ffffffff-ffff-ffff-ffff-ffffffffffff), added more recently in RFC 9562, is the highest possible UUID value — occasionally useful as an explicit upper-bound sentinel.
Can I generate multiple UUIDs at once?
Yes — set "How many" to generate up to 100 at a time, one per line, ready to copy straight into a spreadsheet, test fixture, or seed script.