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UUID / GUID Generator

Generate UUID v4, v1, and bulk UUIDs — cryptographically secure

Free Client-Side No Login No Storage
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How to Use the UUID / GUID Generator

  1. Click Generate to create a new UUID v4.
  2. Use Bulk generate to create multiple UUIDs at once.
  3. Copy individual UUIDs or download the full list.

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal characters. UUID v4 is randomly generated, making collisions statistically impossible (1 in 5.3×10³⁶).

Common uses

  • Database primary keys — avoid sequential IDs that expose record counts
  • Session tokens — generate unique session identifiers
  • File naming — unique filenames for uploads
  • API correlation IDs — trace requests across distributed systems

What is a UUID?

A UUID (Universally Unique Identifier), also called GUID, is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal characters (e.g., 550e8400-e29b-41d4-a716-446655440000). UUID v4 is randomly generated using a cryptographically secure random number generator, making collisions statistically impossible (1 in 5.3×10³⁶ chance).

Common Uses

  • Database primary keys — avoids sequential IDs that expose record counts
  • Distributed systems — generate unique IDs without a central coordinator
  • File naming — unique filenames for user uploads to avoid collisions
  • Session tokens and correlation IDs for request tracing

Frequently Asked Questions

What is the difference between UUID v1 and UUID v4?

UUID v1 is generated from the current timestamp and MAC address of the machine — it encodes when and where it was created. UUID v4 is purely random. For most use cases, v4 is preferred because it doesn't leak machine or time information.

Can two UUIDs ever be the same?

In theory yes, in practice no. The probability of generating a duplicate UUID v4 is approximately 1 in 5.3 undecillion. You would need to generate 1 billion UUIDs per second for 85 years to have a 50 % chance of a single collision.

Is UUID the same as GUID?

Yes. GUID (Globally Unique Identifier) is Microsoft's term for the same concept. They follow the same RFC 4122 standard and are interchangeable.