UUID Generator

Generate random UUIDs (v4) and GUIDs. Copy with one click. Perfect for developer testing.

Generate Single UUID

Generate Multiple UUIDs

UUID v4 — randomly generated. Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where y is 8, 9, A, or B.

About the UUID Generator

UUIDs (Universally Unique Identifiers) are 128-bit values used to uniquely identify records, files, or objects in distributed systems. They're a fundamental building block in database design, API development, and software architecture. Our UUID Generator creates version 4 (random) UUIDs using your browser's crypto.randomUUID() API for true randomness. Generate single or bulk UUIDs instantly.

What Is UUID Generator?

A UUID (also called a GUID in Microsoft ecosystems) is a 128-bit identifier rendered as 32 hexadecimal digits grouped as 8-4-4-4-12, for example '550e8400-e29b-41d4-a716-446655440000'. The total number of possible UUIDs is about 3.4 × 10^38, so randomly generated values are for all practical purposes unique without any central coordination — two independent machines can both generate IDs and almost never collide. Version 4 UUIDs, the most common today, derive all 122 of their non-version bits from a random source, which is why they pair naturally with a cryptographic RNG. Other versions exist: version 1 is time- and node-based, version 3 and 5 are name-based (hashed), and version 7 is time-ordered for better database index locality. UUIDs are the standard identifier format for REST APIs, database primary keys, distributed job IDs, and component identifiers.

How to Use

  1. Click 'Generate UUID' to create a single random UUID (v4).
  2. The UUID appears immediately in the output field — click 'Copy' to copy it.
  3. To generate multiple UUIDs at once, enter a quantity (1 to 50) and click 'Generate Multiple'.
  4. Each UUID follows the standard 8-4-4-4-12 hexadecimal format.
  5. Use generated UUIDs as database primary keys, API request IDs, or unique file identifiers.

Common Use Cases

  • Generating database primary keys without a central counter or sequence
  • Assigning unique request and correlation IDs in distributed services
  • Creating unique file or directory names in batch processing scripts
  • Producing test fixtures and mock identifiers during development
  • Tagging events, spans, or telemetry entries for observability platforms

Examples

Input
Generate v4
Output
e.g. 3f2504e0-4f89-11d3-9a0c-0305e82c3301

Format: 8-4-4-4-12 hexadecimal digits. The '4' marks the version.

Tips & Best Practices

  • UUID v4 is random — not based on time or machine ID — making it suitable for privacy-sensitive use cases.
  • UUIDs are 36 characters with hyphens. Consider removing hyphens if your system requires compact format.
  • The collision probability of UUID v4 is astronomically low — effectively zero for practical applications.
  • This tool uses the native crypto.randomUUID() method, ensuring cryptographically secure randomness.

Frequently Asked Questions

Are generated UUIDs guaranteed unique?

Not mathematically guaranteed, but the probability of a collision is astronomically small. For version 4 UUIDs you would need to generate billions before the chance of even one collision became non-trivial, which is why they are treated as unique in practice.

What is the difference between a UUID and a GUID?

They are the same thing. 'GUID' (Globally Unique Identifier) is Microsoft's term, while 'UUID' is the IETF standard name (RFC 4122). The format and bit layout are identical; only the label differs.

Should I use UUIDs as database primary keys?

They are a good choice for distributed systems where records are created on different nodes. The trade-off is that random UUIDs fragment indexes and are larger than an integer key. For write-heavy tables, consider time-ordered UUIDs (version 7) to preserve locality.

Can I decode a UUID to find out when or where it was made?

Only for version 1 (which embeds time and the machine's MAC address) and version 7 (which embeds a timestamp). Version 4 UUIDs contain no identifying information, which makes them privacy-friendly.

This uuid generator runs entirely in your browser. No data is uploaded to any server. Your privacy is completely protected.

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