UUID Decoder

Canonical, uppercase, braced, urn:uuid:, undashed, 0x-prefixed or base64. All of them decode.

Holding something that is not a UUID? The universal ID decoder reads ULIDs, KSUIDs, ObjectIDs, snowflakes and more.

What does it tell you?

Every UUID states its own version and variant in fixed bit positions, and some versions carry more than that. v1, v2 and v6 contain the moment they were created and the MAC address of the machine that created them. v7 contains a plain Unix millisecond timestamp.

v3, v4 and v5 hold nothing recoverable: a v4 is random, and v3 and v5 are one-way hashes of a name you would have to already know.

Two UUIDs are reserved rather than versioned. The all-zero one is named as the nil UUID and the all-one one as the max UUID, with a note explaining why their version and variant rows read the way they do.

What this accepts

A UUID gets quoted, wrapped and squeezed on its way through a log file, a URL or a cookie. Every shape below decodes, in either case, with surrounding quotes and whitespace ignored.

Canonical: f47ac10b-58cc-4372-a567-0e02b2c3d479
Uppercase: F47AC10B-58CC-4372-A567-0E02B2C3D479
Braced: {f47ac10b-58cc-4372-a567-0e02b2c3d479}
URN: urn:uuid:f47ac10b-58cc-4372-a567-0e02b2c3d479
No dashes: f47ac10b58cc4372a5670e02b2c3d479
Hex literal: 0xf47ac10b58cc4372a5670e02b2c3d479
Base64: 9HrBC1jMQ3KlZw4CssPUeQ==

All seven are the same 128 bits, so they all produce the same reading.

Why it matters

If your system hands out v1 UUIDs, it is publishing hardware identity and precise creation times to anyone who receives one. That is often fine. It is occasionally a leak, and it is worth knowing which.

Decoding happens entirely in your browser. The UUID you paste is never sent anywhere.