Regex for UUID Validation — v1, v3, v4, v5, and v7

Regex for UUID Validation

A UUID is a 128-bit identifier formatted as 8-4-4-4-12 hexadecimal digits separated by hyphens. RFC 4122 (and the updated RFC 9562 for v6–v8) specifies the version digit (13th nibble) and variant bits (17th nibble).

Generic UUID Pattern

^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$

This matches any UUID-shaped string regardless of version.

Strict RFC-Compliant Pattern

^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}$

The third group starts with the version digit (1–8), and the fourth group starts with 8, 9, a, or b (variant bits 10xx).

Version-Specific Patterns

Version	Pattern (third group prefix)
v1 (timestamp)	[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-1[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}
v4 (random)	[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-4[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}
v7 (time-ordered)	[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-7[0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}

Tested Examples

Input	Generic	Strict
f47ac10b-58cc-4372-a567-0e02b2c3d479	yes	yes (v4)
550e8400-e29b-41d4-a716-446655440000	yes	yes (v1)
00000000-0000-0000-0000-000000000000	yes	no (nil UUID)
f47ac10b58cc4372a5670e02b2c3d479	no	no (no hyphens)
g47ac10b-58cc-4372-a567-0e02b2c3d479	no	no (g is not hex)

The Nil UUID

00000000-0000-0000-0000-000000000000 is reserved by RFC 4122 and is technically not a valid generated UUID. The strict pattern above rejects it because the version digit is 0.

Trim Curly Braces

Some systems (Windows GUIDs, .NET) wrap UUIDs in { }. Strip them before matching, or extend the pattern: ^\{?…\}?$.