UUID Generator
Generate and validate UUIDs (v4 random, v1 timestamp)
Calculator
Alternative Formats
Bulk Generation
Validate UUID
About UUIDs
- UUID v4: Randomly generated, most commonly used. 122 bits of randomness.
- UUID v1: Based on timestamp and MAC address. Contains creation time.
- Format: 8-4-4-4-12 hexadecimal characters (32 hex digits + 4 hyphens)
- Uniqueness: Probability of collision is astronomically low (~10^-37)
How to Use
Generate unique identifiers
Select version
Choose UUID version (v4 recommended)
Generate
Click to create new UUID
Generate bulk
Create multiple UUIDs at once
Copy
Copy with or without hyphens
Frequently Asked Questions
UUID (Universally Unique Identifier) is a 128-bit identifier. Format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. Used for database keys, session IDs, distributed systems. Version 4 (random) is most common. Probability of collision is astronomically low.
V1: timestamp + MAC address (reveals info). V4: random (most common, recommended). V3/V5: namespace + name hash (deterministic). V6/V7: sortable timestamp-based (newer). Use V4 unless you need specific properties.
UUIDs: work offline, merge-friendly, no central authority, hide sequence info. Auto-increment: smaller, faster indexing, human readable. Use UUID for distributed systems. Use auto-increment for single-database with performance priority.
V4 UUID has 122 random bits = 5.3×10^36 possibilities. Youd need to generate 1 billion UUIDs per second for 100 years to have 50% chance of one collision. In practice, collisions are not a concern.
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