Random UUID Generator

Create universally unique identifiers for your projects

Options

Generated UUIDs

Select UUID Version

Choose between v1 (timestamp-based), v3/v5 (namespace-based), or v4 (random).

Set Options

Specify how many UUIDs to generate and format options like uppercase or hyphen removal.

Generate

Click the Generate button to create your UUIDs.

Copy or Export

Copy individual UUIDs or export the entire list as TXT/CSV.

Tip: For v3/v5 UUIDs, you'll need to provide a namespace UUID and a name to hash.

Understanding UUIDs and Randomness

What This Tool Generates

This tool creates Universally Unique Identifiers (UUIDs) following RFC 4122 standards. UUIDs are 128-bit identifiers designed to be unique across space and time, with a probability of collision so low it's practically zero for most applications.

Common Use Cases:

  • Database keys: Primary keys for distributed databases
  • Session identifiers: Web application sessions
  • File names: Unique temporary file naming
  • API tokens: Unique access tokens
  • Event tracking: Unique event identifiers
  • Distributed systems: Unique message IDs

UUID Version Differences

Version Type Use Case Collision Risk
v1 Time-based Time-ordered IDs Very low
v3 MD5 hash Deterministic names Depends on input
v4 Random General purpose Extremely low
v5 SHA-1 hash Deterministic names Depends on input

Randomness and Fairness

UUID v4 (Random): Uses your browser's cryptographic random number generator (crypto.getRandomValues()), which provides cryptographically strong randomness suitable for security-sensitive applications. For other types of random data needs, you might explore our random number generator for numeric sequences or the random hex code generator for color values.

Distribution Behavior: Each bit in a UUID v4 has approximately 50% probability of being 0 or 1. The randomness is uniform across the entire 128-bit space.

Important: While UUID v4 uses cryptographically strong randomness, this tool is for development/testing. For production security systems, use dedicated security libraries.

Limitations and Considerations

  • Not a password generator: UUIDs are not designed to be passwords or secrets
  • Length: UUIDs are 36 characters (32 hex + 4 hyphens)
  • Readability: Not human-friendly like random words, which is why tools like our random word generator serve different purposes
  • Deterministic versions: v3 and v5 always produce the same output for identical inputs
  • Browser dependency: Quality depends on browser's crypto implementation

Expected Collision Probability:

With UUID v4, you would need to generate approximately 2.71 quintillion UUIDs to have a 50% chance of a single collision. This makes collisions practically impossible for most applications.

Privacy and Security

No Tracking, No Storage: All UUID generation happens locally in your browser. No identifiers are sent to any server. Your history is stored only in your browser's local storage and can be cleared at any time.
Tool logic reviewed: July 2025
Runs entirely client-side

Frequently Asked Questions

UUIDs are designed to be unique for practical purposes. The probability of generating duplicate UUID v4 values is astronomically low (about 1 in 2.71 quintillion for a 50% collision chance). For v3/v5, uniqueness depends on input uniqueness.

v4: General purpose, completely random. v1: When you need time-ordering. v3/v5: When you need to generate the same UUID from the same inputs (like creating UUIDs from URLs or names).

Yes, for UUID generation. However, always test integration in your environment. For mission-critical systems, consider using established UUID libraries in your programming language directly.

Example Applications

Database Record IDs: users.id = "a1b2c3d4-e5f6-4789-0123-456789abcdef"
API Request IDs: X-Request-ID: 550e8400-e29b-41d4-a716-446655440000
File Upload Names: upload_550e8400e29b41d4a716446655440000.pdf
Distributed Tracing: trace-id: 123e4567-e89b-12d3-a456-426614174000

Related Tools

This tool is part of our randomness suite. When you need simpler numeric identifiers, our random number generator is often a better choice. For creating readable test data, consider using the random word generator to produce memorable content. Developers working with color systems frequently pair UUIDs with our random hex code generator for complete testing scenarios.