Example
[VALID] v1 123e4567-e89b-12d3-a456-426614174000
UUID Validator
Validate UUIDs (v1–v5, nil, namespace forms) instantly in your browser. Free online UUID validator that checks format and version — no uploads.
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- UUID(s) to validate — enter a value. A typical UUID(s) to validate would be e.g. 123e4567-e89b-12d3-a456-426614174000.
- Allowed versions — enter a choice from the options.
- Review your results — the key output is highlighted, with supporting figures below.
Loading calculator…
Results
Validation report
| Detail | Value |
|---|---|
| Valid UUIDs | |
| Invalid UUIDs | |
| UUIDs checked |
What is this calculator for?
Verify that values are well-formed UUIDs and, optionally, filter by the standard version.
How to Use This Calculator
Enter the values below, then press Calculate (or press Enter). The calculator updates your results instantly. Try different values to see how your inputs change the outcome.
- UUID(s) to validate — enter a value. A typical UUID(s) to validate would be e.g. 123e4567-e89b-12d3-a456-426614174000.
- Allowed versions — enter a choice from the options.
- Review your results — the key output is highlighted, with supporting figures below.
What You'll Need
- UUID(s) to validate
- a value · required
- Allowed versions
- a choice from the options (Any version (nil + v1–v5), Only v4 (random), Only v1 (time-based), Any except nil) · optional
About This Calculator
This validator tests each UUID against the canonical 8-4-4-4-12 hex format (RFC 4122), confirms the version digit (1–5) and the v4/v5 variant marker, and optionally tightens the allowed version set.
Line-by-line results show VALID/INVALID plus the inferred version, and the nil UUID (all zeros) is recognized. It accepts one or many UUIDs, newline-separated.
Validation runs entirely in your browser.
Worked Examples
Frequently Asked Questions
Can you tell if a UUID is real, not just formatted?
No — UUIDs are randomly generated, so there is no way to verify authenticity. This tool checks format, version, and variant only.
What is the nil UUID?
It is all zeros (00000000-0000-0000-0000-000000000000), technically a valid UUID that no engine generates. The tool flags it by default.