DNS
Version 1
Timestamp + node based
—Version 3
Namespace + name (MD5)
9073926b-929f-31c2-abc9-fad77ae3e8ebVersion 4
Random (most common)
—Version 5
Namespace + name (SHA-1)
cfbff0d1-9375-5685-968c-48ce8b15ae17Version 7
Time-ordered, sortable
——9073926b-929f-31c2-abc9-fad77ae3e8eb—cfbff0d1-9375-5685-968c-48ce8b15ae17—Generate RFC 4122 UUIDs and Microsoft GUIDs — versions 1, 3, 4, 5, and 7 — instantly in your browser. Format them with uppercase, braces, or no hyphens, and copy with one click. No sign-up, nothing stored.
A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify information without a central authority. Written as 32 hexadecimal digits in five hyphen-separated groups (8-4-4-4-12), UUIDs are unique enough that you can generate them independently across systems with virtually no risk of collision.
GUID (Globally Unique Identifier) is Microsoft's name for the same concept, commonly shown in uppercase and wrapped in curly braces. This tool generates both and lets you switch formatting to match whatever your platform expects.
The most widely used UUID — 122 random bits generated with the browser's cryptographic RNG.
Millisecond timestamp prefix makes these sortable, ideal as modern database primary keys.
Combines a Gregorian-epoch timestamp with a random node, in the classic time-based layout.
Deterministic UUIDs hashed from a namespace + name using MD5 (v3) or SHA-1 (v5).
Toggle uppercase, curly braces { }, and hyphens to match the Microsoft GUID style you need.
Every identifier is generated in your browser. Nothing is sent to a server or stored.
A fresh v1, v4, and v7 identifier is produced instantly — click again for new ones.
For v3 and v5, pick a namespace (DNS, URL, OID, X.500) and type a name to derive a deterministic UUID.
Flip the uppercase, braces, or hyphens toggles to match the casing and GUID style your system expects.
Copy any single value, or use Copy All to grab every version at once.
They are the same thing. UUID (Universally Unique Identifier) is the term from the RFC standards, while GUID (Globally Unique Identifier) is Microsoft's name for the same 128-bit value. GUIDs are often written in uppercase and wrapped in curly braces.
Use v4 for general-purpose random IDs — it is the safe default. Use v7 when you want time-sortable identifiers for database keys. Use v3 or v5 when you need a deterministic UUID derived from a name. v1 is mainly for legacy compatibility.
v4 has 122 bits of randomness, making collisions astronomically unlikely. v7 and v1 combine a timestamp with random bits. v3 and v5 are deterministic — the same namespace and name always produce the same UUID, which is the intended behavior.
Yes. Random values use the browser's crypto.getRandomValues, and every UUID is generated entirely on your device. Nothing is transmitted to a server or stored.
Namespace UUIDs hash a namespace identifier together with a name to produce a reproducible UUID. The predefined namespaces (DNS, URL, OID, X.500) come from RFC 4122 so that the same name in the same namespace yields the same UUID everywhere.
v7 places a millisecond timestamp at the start of the UUID, so newly generated values sort in roughly chronological order. That improves index locality and insert performance compared to fully random v4 keys.
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