Free Online UUID Generator (v1 & v4)

Generate universally unique identifiers (UUIDs) instantly. Choose between UUID v1 (time-based) and UUID v4 (random). Generate up to 20 UUIDs at once and validate existing ones.

Related Tools

← All Tools Hash Generator Unix Timestamp JSON Formatter

Version

Count

Generated UUIDs

Validate a UUID

Frequently Asked Questions

What is the difference between UUID v1 and v4?

UUID v1 is time-based: it incorporates the current timestamp and MAC address, making it sortable but potentially revealing system info. UUID v4 is randomly generated with 122 bits of entropy, making it suitable for most security-sensitive applications.

Are UUIDs truly unique?

UUID v4 has 2^122 possible values — about 5.3 × 10^36. The probability of a collision in practice is negligible. You would need to generate a billion UUIDs per second for 100 years to have a 50% chance of a single collision.

What is the difference between UUID and GUID?

GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. They are the same format (8-4-4-4-12 hex characters) and are interchangeable in virtually all contexts.