UUID Generator

Version 4 is entirely random (except for the version and variant bits), making it the simplest choice for most applications. Version 7 encodes a millisecond-precision Unix timestamp in the first 48 bits, so UUIDs generated later sort lexicographically after earlier ones — a significant advantage when using UUIDs as database primary keys, since it avoids index fragmentation.

Traditional V1 UUIDs encode the host machine's MAC address, which can reveal information about the generating system. This generator substitutes a cryptographically random 48-bit value in place of the MAC address, which mitigates that risk. For new projects, Version 7 is generally the better choice when time-ordering is needed.

Collisions are theoretically possible but astronomically unlikely. A Version 4 UUID has 122 bits of randomness; you would need to generate approximately 2.71 quintillion UUIDs before reaching a 50% probability of a single collision.

Removing the hyphens produces a compact 32-character hexadecimal string. Some databases, APIs, and libraries accept UUIDs in this format. The underlying value is identical — the dashes are purely cosmetic separators.

UUID hexadecimal characters are case-insensitive. The RFC recommends lowercase output, but some systems or style guides prefer uppercase. The Uppercase option converts a–f to A–F across the entire output.

No. All generation are performed entirely in your browser. No data is ever sent to a server or saved.