Free Online UUID/GUID Generator
Generate unique UUIDs/GUIDs instantly for testing and development. Free online tool with multiple versions and output formats.
Generation Settings
How UUID/GUID Works
UUID Structure
• 128 total bits (32 hexadecimal characters)
• Format: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
• Universal unique identifier
• RFC 4122 standard international
Uniqueness Guarantee
• Minimal probability of collision
• Distributed generation without coordination
• Safe use in distributed systems
• Industry standard for unique IDs
UUID Versions
Most used • Completely random
Ideal for record IDs, tokens, API keys
Timestamp-based • MAC address
Useful when temporal order is important
Namespace-based • MD5 hash
Deterministic for same input
Namespace-based • SHA-1 hash
More secure than v3, deterministic
Frequently Asked Questions about UUID/GUID
Are UUID and GUID the same thing?
Yes, they are the same concept. UUID is the standard term (RFC 4122) and GUID is the term used by Microsoft.
Which UUID version should I use?
UUID v4 is the most common and recommended for most cases, as it is completely random and does not reveal information.
Are UUIDs really unique?
The probability of collision is extremely low (1 in 5.3x10^36 for UUID v4), being considered unique in practice.