UUID/GUID Generator (v4)
Generate unique UUIDs and GUIDs instantly. Create one or batch-generate multiple random v4 UUIDs with one-click copy.
Runs in your browser. No data leaves your device.
Frequently Asked Questions
How does the UUID Generator work?
The tool generates version 4 UUIDs using the Web Crypto API's crypto.getRandomValues() to fill a 16-byte array with cryptographically secure random numbers. It then sets the version bits (0100 in bits 48-51) and variant bits (10 in bits 64-65) per RFC 4122, and formats the bytes as a hyphenated hexadecimal string in the standard 8-4-4-4-12 pattern.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal digits in groups like 550e8400-e29b-41d4-a716-446655440000. UUIDs are used as database primary keys, session IDs, and unique references.
Are the generated UUIDs truly unique?
Yes. Version 4 UUIDs are generated from cryptographically secure random numbers. The probability of generating two identical UUIDs is astronomically small -- about 1 in 5.3 x 10^36.
Can I generate multiple UUIDs at once?
Yes. Set the batch size and generate multiple UUIDs in a single click. Copy them all at once or individually. Useful when you need to seed a database or create test data.