UUID Generator
Generate random UUID v4 (GUID) identifiers instantly. Bulk generation supported. Perfect for databases, testing, and development. Free online tool.
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How to Use UUID Generator
- Click "Generate" to create a new random UUID
- Use the quantity selector to generate multiple UUIDs at once
- Click on any UUID to copy it to your clipboard
- Click "Generate" again for new unique identifiers
- All UUIDs are RFC 4122 version 4 compliant
About UUID Generator
Generate universally unique identifiers (UUIDs) instantly with our free UUID Generator. UUIDs (also known as GUIDs - Globally Unique Identifiers) are 128-bit identifiers that are statistically guaranteed to be unique across space and time.
What is a UUID? A UUID is a 128-bit number represented as 32 hexadecimal digits, displayed in five groups separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Our generator creates Version 4 UUIDs, which are generated using random or pseudo-random numbers.
UUID v4 Characteristics: - Format: 8-4-4-4-12 hexadecimal digits (36 characters with hyphens) - Example: 550e8400-e29b-41d4-a716-446655440000 - Uniqueness: 2^122 possible values (5.3 × 10^36 combinations) - Collision Probability: Astronomically low (would need to generate 1 billion UUIDs per second for 85 years to have 50% chance of collision)
Common UUID Use Cases: - Database Primary Keys: Replace auto-increment IDs for distributed systems - Session Identifiers: Unique session tokens for web applications - API Request IDs: Track and correlate requests across services - File Naming: Generate unique filenames to prevent collisions - Testing: Create unique test data for development - Transaction IDs: Track unique transactions across systems
Generator Features: - Cryptographic Randomness: Uses crypto.getRandomValues() for true randomness - Bulk Generation: Generate multiple UUIDs at once - Instant Copy: One-click copy to clipboard - Standard Format: RFC 4122 compliant v4 UUIDs
All generation happens locally in your browser with no server communication, making it safe for generating IDs for sensitive applications.
Common Use Cases
Frequently Asked Questions
Are UUIDs guaranteed to be unique?
Practically, yes. The probability of generating duplicate UUIDs is so astronomically low it's considered impossible in practice. You'd need to generate billions of UUIDs per second for centuries to have a meaningful chance of collision.
What's the difference between UUID versions?
Version 1 uses timestamp + MAC address. Version 3 uses MD5 hash of namespace + name. Version 4 (what we generate) uses random numbers. Version 5 uses SHA-1 hash. Version 4 is most common for general purposes.
Can I use UUIDs as database primary keys?
Yes, UUIDs are excellent for distributed systems where you can't coordinate ID generation. However, they use more storage than integers and random UUIDs can cause index fragmentation. Consider UUIDv7 for sorted IDs.
Are the generated UUIDs cryptographically secure?
Yes. We use the Web Crypto API (crypto.getRandomValues()) which provides cryptographically strong random numbers, making these UUIDs suitable for security-sensitive applications like session tokens.
Why are there hyphens in UUIDs?
Hyphens are part of the canonical format defined in RFC 4122. They separate the UUID into five groups for readability. For storage efficiency, you can remove hyphens, but include them when displaying to users.
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