UUID Generator
Free online tool to quickly generate UUID v4
Generation Options
What is a UUID (Universally Unique Identifier)?
UUID (Universally Unique Identifier) is a 128-bit identifier that guarantees uniqueness across networks. UUID v4 is generated based on random values, and with an extremely low probability of duplication, it is widely used in various fields such as database primary keys, API tokens, and session identifiers.
UUID v4 Format
UUID v4 consists of 32 hexadecimal characters in the format 8-4-4-4-12. Example: 550e8400-e29b-41d4-a716-446655440000. The first character of the third group is always 4 to indicate the version, and the first character of the fourth group is one of 8, 9, a, or b.
Key Use Cases
- Use as database primary key
- Generate unique identifiers in distributed systems
- API request tracking and logging
- Generate filenames or temporary tokens
Frequently Asked Questions
UUID v4 uses 122 bits of random data, allowing approximately 5.3 x 10^36 unique values. The probability of duplication is extremely low even when generating billions (approximately 2.71 x 10^18 would need to be generated for a 50% chance of one duplicate), making it practically unique.
Yes, hyphens are merely separators for readability and do not affect the uniqueness of a UUID. A 32-character hexadecimal string without hyphens represents the same UUID. However, the RFC 4122 standard recommends the format with hyphens.
This tool generates UUIDs based on cryptographically secure random numbers using the browser's crypto.randomUUID() or crypto.getRandomValues() API. All generation is processed locally in the browser, and no data is transmitted to a server.
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