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UUID Generator

UUID Generator
Generator

UUID Validator

About UUIDs

A UUID (Universally Unique Identifier) is a 128-bit number used to identify information in computer systems. The probability of generating duplicate UUIDs is extremely low.

  • Version 4: Generated using random numbers (recommended)
  • Version 1: Based on timestamp and MAC address
  • NIL: Special UUID with all zeros

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What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Also known as GUID (Globally Unique Identifier) in Microsoft systems, UUIDs are designed to be unique across space and time.

The standard format is 32 hexadecimal digits displayed in five groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

UUIDs are widely used in databases, distributed systems, and software development for creating unique identifiers without requiring a central authority.

UUID Versions

Version 4 (Random)

Generated using random or pseudo-random numbers. This is the most commonly used version and recommended for most applications.

Version 1 (Time-based)

Generated using the current timestamp and MAC address. Useful when you need chronologically sortable identifiers.

Version 3 & 5 (Name-based)

Generated by hashing a namespace identifier and name. Version 3 uses MD5, Version 5 uses SHA-1.

NIL UUID

A special UUID with all bits set to zero. Used as a placeholder or to represent "no value" in systems.

Frequently Asked Questions

Can UUIDs ever collide?

While theoretically possible, the probability is astronomically low. For UUID v4, you would need to generate about 2.71 quintillion UUIDs to have a 50% chance of one collision. In practical terms, this is not a concern.

What's the difference between UUID and GUID?

UUID (Universally Unique Identifier) and GUID (Globally Unique Identifier) are essentially the same thing. GUID is the term used by Microsoft, while UUID is the more universal standard term defined in RFC 4122.

Which UUID version should I use?

For most applications, UUID v4 (random) is recommended due to its simplicity and excellent randomness. Use v1 if you need time-sortable identifiers. Use v3/v5 if you need deterministic UUIDs based on names.

Are these UUIDs secure for sensitive applications?

UUID v4 uses cryptographically secure random number generation when available (via crypto.randomUUID). However, UUIDs are identifiers, not secrets. For authentication tokens or passwords, use dedicated cryptographic tools.