UUID Generator
Generate random UUID v4 values.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value formatted as 32 hexadecimal digits in five groups (e.g., 550e8400-e29b-41d4-a716-446655440000). Version 4 UUIDs are generated using random or pseudo-random numbers, giving over 5.3 undecillion possible values-making collisions virtually impossible without coordination between systems.
How to Use
- Set the number of UUIDs you want to generate (1 to 100).
- Click Generate to create cryptographically random v4 UUIDs.
- Copy individual UUIDs or use "Copy All" to get them all at once.
Frequently Asked Questions
What are UUIDs used for?
UUIDs are commonly used as database primary keys, API request identifiers, session tokens, and anywhere you need globally unique IDs without a central authority assigning them. They're especially valuable in distributed systems where multiple servers create records simultaneously. Unlike auto-incrementing IDs, UUIDs can be generated client-side before data reaches the server.
Can UUID v4 values collide?
The probability is astronomically low. You would need to generate about 2.71 quintillion UUIDs to have a 50% chance of a single collision. For practical purposes, they are unique. To put this in perspective, if you generated one billion UUIDs per second, it would take about 85 years to reach a 50% collision probability.
What is the difference between UUID versions?
V1 uses timestamp and MAC address, V4 is purely random, and V5 is derived from a namespace and name via SHA-1. V4 is most common because it requires no coordination or input data. The newer V7 (RFC 9562) combines a Unix timestamp prefix with random bits, giving you both uniqueness and sortability-making it ideal for database primary keys where insert order matters.
