Free UUID Generator
Generate cryptographically random version 4 UUIDs using the browser's native crypto.randomUUID(). Bulk generation up to 100 UUIDs. Copy individually or all at once.
About UUID v4 Generator
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. Version 4 UUIDs are randomly generated, making them statistically unique — the probability of collision is negligible even across billions of generated IDs.
This tool uses crypto.randomUUID(), available in all modern browsers, which uses a cryptographically secure pseudo-random number generator (CSPRNG). The "4" in the third group identifies it as version 4.
Common Uses for UUIDs
- Primary keys in databases without auto-increment (distributed systems)
- Unique file or object names in cloud storage
- Session and transaction identifiers
- Idempotency keys for API requests
- Tracking IDs in analytics and logging systems
Frequently Asked Questions
GUID (Globally Unique Identifier) is Microsoft's implementation of UUID. They are functionally identical — 128-bit identifiers with the same format. The terms are used interchangeably in most contexts.
Theoretically yes, but the probability is astronomically low. With UUID v4, there are 2^122 possible values (~5.3 × 10^36). You would need to generate approximately 2.7 × 10^18 UUIDs to have a 50% chance of a collision.
Yes. UUID characters (hex digits and hyphens) are all URL-safe and do not need percent-encoding. They are commonly used as URL path segments for resource IDs in REST APIs.