UUID Generator

Generate cryptographically random UUID v4 identifiers. Generate one or hundreds at a time, in multiple formats, and copy them all with one click.

crypto.randomUUID() · Cryptographically secure
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UUID format breakdown

  • xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx
  • 32 hexadecimal characters in 5 groups
  • The "4" marks it as version 4 (random)
  • The "y" position marks the variant bits
  • 128 bits total — 122 random bits

Common uses

  • Primary keys in databases
  • Session tokens and correlation IDs
  • File names to prevent collisions
  • Idempotency keys in APIs
  • Unique identifiers in distributed systems

Frequently Asked Questions

Are these UUIDs truly random?

Yes. This tool uses crypto.randomUUID(), which is seeded by the operating system's cryptographically secure random number generator — the same source used for cryptographic key generation.

Can two generated UUIDs ever be the same?

Theoretically yes, but statistically impossible in practice. UUID v4 has 122 random bits. The probability of a collision across 1 billion UUIDs is roughly 1 in 800 million trillion.

What's the difference between UUID v1 and v4?

UUID v1 is generated from a timestamp plus the device's MAC address — making it predictable and potentially identifying. UUID v4 is fully random. Always use v4 for security-sensitive contexts.

Is UUID the same as GUID?

Yes. GUID (Globally Unique Identifier) is Microsoft's name for the same standard. The format and specification are identical.