Free Online UUID Generator

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify resources in computer systems. It is formatted as 32 hexadecimal characters separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are also known as GUIDs (Globally Unique Identifiers) in Microsoft ecosystems.

UUID v1 is generated using a timestamp and the machine's MAC address, which means it can reveal information about when and where it was created. UUID v4 is generated using random or pseudo-random numbers, making it the preferred choice for most applications because it does not leak any identifying information.

While theoretically possible, the probability of generating two identical UUID v4 values is astronomically low — approximately 1 in 5.3 × 10^36. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision, making duplicates effectively impossible in practice.

UUID v4 values generated with a cryptographically secure random number generator (like the Web Crypto API used by this tool) have strong randomness. However, UUIDs are not designed as security tokens. For authentication tokens or API keys, use a dedicated secret generator with higher entropy and proper encoding.

A UUID follows the format xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, where each x is a hexadecimal digit (0–9, a–f). The M digit indicates the UUID version (4 for random), and the N digit indicates the variant (8, 9, a, or b for RFC 4122). The total length is 36 characters including hyphens.

This tool lets you generate up to 100 UUIDs in a single batch. Simply set the quantity you need and click generate. All UUIDs are created instantly in your browser and can be copied to your clipboard with one click.

UUIDs can be generated independently on any machine without coordination, making them ideal for distributed systems, microservices, and offline-first applications. They also prevent information leakage — unlike sequential IDs, UUIDs do not reveal how many records exist or the order in which they were created.

UUIDs are widely used as primary keys in databases, identifiers for API resources, session tokens, correlation IDs in distributed tracing, file names for uploaded content, and transaction identifiers in payment systems. They are supported natively by most programming languages and databases including PostgreSQL, MySQL, and MongoDB.