UUID v4 Generator
Click "Generate" to create UUIDs...
UUID v4 Format
A UUID v4 is a 128-bit number represented as 32 hexadecimal digits displayed in five groups separated by hyphens: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. The "4" indicates the version, and "y" is one of 8, 9, a, or b (variant bits).
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in computer systems. UUID v4 is generated using random or pseudo-random numbers, making it virtually guaranteed to be unique across all systems worldwide.
How to Use
- Select the number of UUIDs to generate (1-100)
- Choose your preferred format options (case, hyphens, braces)
- Click "Generate" to create your UUIDs
- Click the copy icon next to any UUID or "Copy All" to copy everything
Features
- Cryptographically secure random generation using Web Crypto API
- Bulk generation up to 100 UUIDs at once
- Multiple format options: uppercase/lowercase, hyphens, braces
- One-click copy for individual or all UUIDs
- Line numbers for easy reference
FAQ
Are UUID v4 truly unique?
The probability of a collision is extremely low (approximately 1 in 2^122). You would need to generate billions of UUIDs per second for billions of years to have a 50% chance of a single collision.
Can I use UUIDs as database primary keys?
Yes, UUIDs are commonly used as primary keys, especially in distributed systems where auto-increment IDs would cause conflicts. However, consider UUID v7 for better database index performance.
What's the difference between UUID versions?
UUID v1 uses timestamp and MAC address, v4 is fully random, v5 uses namespace and name with SHA-1 hashing. Version 4 is the most commonly used for general purposes.