UUID Generator
Generates v4 and v7 UUIDs (RFC 9562), one at a time or in batches, ready to copy.
Version
Quantity
574a1593-25bc-497c-a9bb-a45f849ba116
54ff6503-ddbf-4a19-984c-a1ba38751cd4
c1ffdb10-e4c0-492c-ba63-17300db6786b
c6ef7a0a-7060-4325-aa4a-7841025dbabd
675da9c3-d5ce-40b6-9eda-e1124c4015fd
e70d94ba-84f4-4145-8731-bdd58079200a
9c699325-2fcf-4820-86fd-3064e460ce66
995bf8a0-26bd-469e-9d08-2aa3b55c854c
41292648-0ae6-4b65-84d3-1b8dc6d41d20
977d697c-bcd9-41cf-8157-5e178ac91fee
When to use each version
| Version | When to use |
|---|---|
| UUID v4 | Fully random IDs, maximum compatibility. |
| UUID v7 | New projects, databases, time ordering, better index performance. |
What a UUID is
A UUID (Universally Unique Identifier) is a 128-bit identifier, standardized by RFC 9562, used to identify something with practical uniqueness — without needing a central server to coordinate generation. It's the de facto standard for primary keys, session IDs, resource names and event correlation in databases, APIs and distributed systems.
What the "Decode" mode does
Takes any UUID — it doesn't need to have been generated by this tool — and identifies version, variant and, when present, the embedded timestamp. Nil UUID and Max UUID (all bits zero or all one) are recognized as special cases from the RFC itself. Timestamp is only decoded for v7 in this version: v1 and v6 use the same epoch, just arranged across different fields, and that conversion hasn't been validated with enough confidence to ship yet.
Frequently asked questions
A 128-bit identifier (RFC 9562) used to name something with practical uniqueness, without needing central coordination.
v4 is fully random (122 bits of entropy) — the most compatible. v7 reserves the first 48 bits for a Unix timestamp, which makes it sortable by time and improves database index performance.
v1 and v6 also carry an embedded timestamp, but they use a different epoch (Gregorian, since 1582) arranged across fields that aren't directly comparable to v7 — decoding them correctly requires a conversion that hasn't been validated with enough confidence for this version of the tool yet.
The field that indicates which bit-layout rule the UUID follows. All versions 1 through 8 use the RFC 4122/9562 variant; NCS and Microsoft/COM are legacy layouts that predate the current standard.
The UUID with all 128 bits set to zero (00000000-0000-0000-0000-000000000000) — defined by RFC 9562 to represent the absence of a value, not an error.
The UUID with all 128 bits set to one (ffffffff-ffff-ffff-ffff-ffffffffffff) — the highest possible value, defined by the same RFC as a "highest possible value" sentinel.
No. A UUID identifies something with practical uniqueness — it wasn't designed to be a secret. v7 in particular should never be used as a session token/key: a good part of its bits is a predictable timestamp, not randomness.
Only if it's v7 (v1/v6 aren't decoded in this version yet) — Decode mode shows the embedded timestamp. A v4 UUID carries no information about when it was generated.