Developer UUID tools
UUID Format
A UUID is normally written as 36 characters with hyphens in an 8-4-4-4-12 pattern, or as 32 hexadecimal characters without hyphens.
UUID 8-4-4-4-12 pattern
The canonical UUID string pattern is 8 hexadecimal characters, then 4, 4, 4, and 12 characters separated by hyphens.
Example: 123e4567-e89b-12d3-a456-426614174000.
UUID length
A hyphenated UUID is 36 characters long: 32 hexadecimal characters plus 4 hyphens. Without hyphens, the UUID string is 32 characters long.
The value represents 128 bits. Some systems store UUIDs as binary values instead of strings to save space.
Version and variant positions
The UUID version digit is the first character of the third group. For UUID v4, that digit is 4. For UUID v7, that digit is 7.
The variant is encoded near the start of the fourth group. Standard UUIDs normally use 8, 9, a, or b there.
FAQ
How many characters are in a UUID?+
A UUID has 36 characters with hyphens or 32 hexadecimal characters without hyphens.
What is the UUID pattern?+
The common pattern is 8-4-4-4-12, using hexadecimal characters separated by hyphens.
Can UUIDs be uppercase?+
Yes. UUID hexadecimal characters are case-insensitive, though lowercase is common in many systems.