Question 1

Are generated UUIDs unique?

Accepted Answer

v4 is based on cryptographically secure random number generation, with a very low collision probability, practically unique in real-world use. Generation is done locally in your browser, with no data uploaded.

Question 2

What's the difference between v4 and v7?

Accepted Answer

v4 is completely random; v7 embeds a millisecond timestamp in the prefix, so it's naturally ordered by generation time, making it more suitable as a database primary key, reducing index fragmentation and improving insertion performance.

Question 3

What's the maximum number that can be generated at once?

Accepted Answer

Up to 1000 can be generated at once, with options for uppercase, remove hyphens, or add braces, and one-click copy all.

UUID Generator

Generation Settings

FAQ