UUID Generator

1. Click "Generate" to create a new UUID.
2. Adjust the count to generate multiple UUIDs at once.
3. Click "Copy" to copy the result to your clipboard.

About UUID Generation

UUIDs are essential for creating unique identifiers in distributed systems, databases, and APIs without requiring a central authority. This tool generates cryptographically random UUID v4 values in your browser.

UUID Versions Explained

UUID v1 combines a timestamp with the machine's MAC address, which makes it unique but leaks information about when and where it was generated. UUID v4 is purely random (122 bits of randomness) and is the most widely used version. UUID v7 is the newer option: it embeds a Unix timestamp in the high bits so UUIDs sort chronologically, which is great for database primary keys. If you need time-ordered IDs, v7 is the modern choice.

UUID vs Auto-Increment IDs

Auto-increment IDs are simple and compact but require a single authority (your database) to assign them. In distributed systems (multiple servers, offline clients, or microservices creating records independently), UUIDs let every node generate IDs without coordination. The tradeoff: UUIDs are 128 bits vs 32-64 for integers, and random v4 UUIDs cause index fragmentation in B-tree databases. That's where v7's time-ordering helps.

Collision Probability

With 122 random bits, UUID v4 has about 5.3 x 10^36 possible values. You'd need to generate around 2.7 billion UUIDs to have a 50% chance of a single collision. In practice, this means collisions won't happen in any real-world system. The random number generator quality matters more than the math. This tool uses the Web Crypto API, which provides cryptographically secure randomness.

For other types of unique identifiers, try our Nano ID Generator for shorter, URL-friendly IDs. You can also generate Random Strings with custom character sets, or create secure credentials with the Password Generator.