UUID Generator

Generate cryptographically random RFC 4122 v4 UUIDs — individually or in bulk.

How many

Format

UUIDs

How to Use This Generator

Choose how many UUIDs you need and their format, then generate and copy.

What is a UUID?

A Universally Unique Identifier — a 128-bit number formatted as 32 hex digits. v4 is random; v1 is time-based.

Can two generated UUIDs be the same?

Practically never. With 122 random bits, collisions are vanishingly rare — far less likely than being struck by lightning.

What do the version and variant bits mean?

The version digit (4) identifies the generation method, and the variant digit (8,9,A,B) marks the RFC layout — both are fixed for v4.

Are uppercase UUIDs different?

No — hex digits are case-insensitive. The format is cosmetic, though some systems expect lowercase consistently.

A generated v4 UUID looks like this:

f47ac10b-58cc-4372-a567-0e02b2c3d479
The 13th digit is always 4 (the version), and the 17th is one of 8, 9, A, B (the variant).
32 hex digits in 5 groups (8-4-4-4-12), 36 characters including hyphens.

Version digit — the 13th character (a fixed 4 for v4) records the generation method per RFC 4122.
Variant digit — the 17th character (8, 9, A or B) marks the RFC layout of the remaining bits.
Format — hyphens, braces or case are cosmetic; the underlying 128-bit value is the same.