UUID Validator and Version Checker
Paste a UUID or GUID to check whether it is well-formed and learn its version and variant. Validation runs in your browser, with optional surrounding braces accepted.
How to validate a UUID
- Paste your UUID into the box. Braces, extra spaces and uppercase are fine.
- Read the valid or invalid indicator that updates as you type.
- When valid, check the detected version, variant and whether it is the nil UUID.
Examples
A valid version 4 UUID
550e8400-e29b-41d4-a716-446655440000
valid: true, version: 4, variant: RFC 4122
The nil UUID
00000000-0000-0000-0000-000000000000
valid: true, version: 0, isNil: true
Frequently asked questions
What format does a valid UUID use?
A UUID is 32 hexadecimal digits split into five hyphen-separated groups of 8-4-4-4-12, for example 550e8400-e29b-41d4-a716-446655440000. This tool also accepts a pair of surrounding braces and ignores letter case.
What does the UUID version mean?
The version is the first digit of the third group and describes how the UUID was made. Common values are 1 through 5, plus the newer 8. It tells you whether the ID is time-based, name-based, random and so on.
What is the difference between v1 and v4?
A version 1 UUID is built from a timestamp and a node identifier, so parts of it are predictable and ordered over time. A version 4 UUID is almost entirely random, which makes it unpredictable but not sortable.
What is the nil UUID?
The nil UUID is all zeros: 00000000-0000-0000-0000-000000000000. It is a valid, special value that usually represents an empty or unset identifier. This tool reports it as valid with version 0 and marks isNil as true.
What is the variant and how is it detected?
The variant is read from the high bits of the 17th hex digit. Most modern UUIDs are the RFC 4122 variant, shown when that digit is 8, 9, a or b. Other ranges map to the older NCS, Microsoft or reserved variants.
Is my UUID sent anywhere?
No. All validation happens locally in your browser, so the UUID you paste never leaves your device.
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