Generate cryptographically secure UUID v4 strings — single or in bulk up to 100. Choose format, validate existing UUIDs, all 100% browser-based.
Click the UUID itself or the Generate button to get a new one instantly.
| Format | Example | Length | Use Case |
|---|---|---|---|
| Standard | 550e8400-e29b-41d4-a716-446655440000 | 36 chars | Most databases, APIs, REST |
| UPPERCASE | 550E8400-E29B-41D4-A716-446655440000 | 36 chars | Legacy systems, Windows |
| No hyphens | 550e8400e29b41d4a716446655440000 | 32 chars | Compact storage, URLs |
| Braces | {550e8400-e29b-41d4-a716-446655440000} | 38 chars | Microsoft COM, Registry |
| URN | urn:uuid:550e8400-e29b-41d4-a716-446655440000 | 45 chars | XML, Semantic Web, RFC 4122 |
Generate a single UUID, bulk generate up to 100, or validate an existing UUID.
Choose standard, UPPERCASE, no-hyphens, braces, or URN format.
Copy individual UUIDs or download all as a .txt file.
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A UUID (Universally Unique Identifier), also called a GUID, is a 128-bit identifier standardized as RFC 4122. Written as 32 hex characters in the format xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, it is designed to be unique across all space and time without a central authority to coordinate issuance.
UUID v4 is randomly generated. It uses crypto.getRandomValues() for cryptographically secure randomness — 122 bits of randomness — making collisions astronomically unlikely (~1 in 5.3×10³⁶ chance). It is the most widely used version because it requires no coordination, no network, no timestamp — just entropy.
UUID v4 has 2¹²² possible values (about 5.3 undecillion). You would have to generate 1 billion UUIDs per second for about 85 years before there is a 50% chance of a single collision. In practice, UUID v4 is considered globally unique for all real-world purposes.
Nothing — they are the same thing. GUID (Globally Unique Identifier) is Microsoft's name for the same RFC 4122 standard UUID format. Both are identical in structure, just different terminology.