UUID Generator
Generate random UUID v4 identifiers instantly
UUID v4 Format Explained
xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
Example: 550e8400-e29b-41d4-a716-446655440000
Example: 550e8400-e29b-41d4-a716-446655440000
Total length: 36 characters (32 hex digits + 4 hyphens)
128 bits split into 5 groups: 8-4-4-4-12 hex digits
Version digit (position 13): Always 4 — indicates UUID v4 (random)
Variant digit (position 17): Always 8, 9, a, or b — indicates RFC 4122 variant
Randomness: 122 random bits, making collisions astronomically unlikely (1 in 5.3 × 1036)
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier that is guaranteed to be unique across space and time. They're widely used in databases, APIs, and distributed systems to identify resources without a central authority.
What is UUID v4?
UUID v4 is a version that uses random or pseudo-random numbers to generate identifiers. It has 122 random bits, making collisions extremely unlikely — about 1 in 5.3 × 1036. It's the most commonly used UUID version.
Are UUIDs generated here truly random?
Yes. This tool uses the browser's
crypto.getRandomValues() API, which provides cryptographically strong random values sourced from the operating system's entropy pool.Can two UUIDs ever collide?
Theoretically yes, but practically no. You'd need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision. That's roughly 1 billion UUIDs per second for 85 years.
Is this free?
Yes. No signup, no limits. Generate as many UUIDs as you need. Everything runs in your browser — nothing is sent to any server.