UUID Generator

Generate random UUID v4 strings instantly. Bulk generate up to 100 UUIDs at once.

Generated UUID v4

Uppercase No hyphens With braces {uuid}

UUID v4 uses 122 bits of cryptographic randomness.

Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

Generated using crypto.randomUUID() — no data sent to servers.

How It Works

Click Generate to create a single UUID v4. Use the bulk mode to generate multiple UUIDs at once. Each UUID is generated using the browser's cryptographically secure random number generator.

A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify objects in distributed systems. UUID v4 is randomly generated and has an astronomically low probability of collision, making it ideal for generating unique IDs without a central authority.

**UUID Format**

A UUID looks like this: `550e8400-e29b-41d4-a716-446655440000`

It is composed of 32 hexadecimal characters separated by hyphens in the pattern 8-4-4-4-12.

**UUID Versions Explained**

- **v1**: Based on timestamp + MAC address (reveals device info — avoid for privacy)
- **v3**: Name-based using MD5 hashing (deterministic)
- **v4**: Fully random (most commonly used — what this tool generates)
- **v5**: Name-based using SHA-1 hashing (deterministic)
- **v7**: Time-ordered random (newest standard, sortable)

**When to Use UUIDs**

- Primary keys in distributed databases where multiple nodes generate IDs independently
- Session and request correlation identifiers
- File names to avoid conflicts across systems
- Resource identifiers in REST APIs

**UUID vs Auto-Increment IDs**

UUIDs are better for distributed systems. Auto-increment integers are better for single-server applications where sequential ordering and small ID size matter for joins and indexes.

**Are UUIDs Truly Unique?**

UUID v4 contains 122 bits of randomness (approximately 5.3 × 10^36 possible values). The probability of generating a duplicate is negligibly small — you would need to generate 1 billion UUIDs per second for 85 years to have a 50% chance of a collision.

**Privacy**

UUIDs are generated using the browser's Web Crypto API. No data is sent to our servers.

Frequently Asked Questions

A UUID (Universally Unique Identifier) is a standardized 128-bit identifier practically guaranteed to be unique across all computers and at all times. Formatted as 32 hex digits in an 8-4-4-4-12 pattern.

GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. They are functionally identical.

UUID v4 is randomly generated using a CSPRNG, making it suitable for identifiers. However, UUIDs are not secrets — do not use them alone as security tokens.

Theoretically yes, but the probability is astronomically low. In practice, UUID v4 collisions do not occur in real-world applications.

UUIDs are better for distributed systems. Auto-increment integers are better for single-server applications where sequential ordering and index size matter.