UUID Generator
Generate UUID v4 strings instantly. Create single or batch UUIDs, toggle uppercase/lowercase, and copy all with one click. Free online GUID generator.
Why Use a UUID Generator?
UUIDs (Universally Unique Identifiers) are essential for generating unique IDs in distributed systems, databases, and applications. UUID v4 uses random values to create identifiers with an astronomically low collision probability. Our generator lets you create single or batch UUIDs instantly, entirely in your browser.
Key Features
- Generate UUID v4 strings using crypto.randomUUID()
- Batch generation — up to 100 UUIDs at once
- Uppercase/lowercase toggle
- Copy individual UUIDs or all at once
- No server calls — fully client-side
How It Works
- Set the number of UUIDs you need (1–100)
- Toggle uppercase if needed
- Click Generate to create UUIDs
- Copy individual or all UUIDs to clipboard
Technical Details
This generator uses the Web Crypto API's crypto.randomUUID() method, which produces RFC 4122-compliant UUID v4 strings. The format is 8-4-4-4-12 hexadecimal digits (e.g., 550e8400-e29b-41d4-a716-446655440000). Bits 6 and 7 of the clock_seq_hi_and_reserved field are set to 1 and 0 respectively, and bit 6 of the time_hi_and_version field is set to 1 (version 4).
Frequently Asked Questions
What is UUID v4?
UUID v4 is a version of Universally Unique Identifier that uses random numbers. It has 122 random bits, providing about 5.3 × 10^36 possible values, making collisions extremely unlikely.
Are these UUIDs cryptographically secure?
Yes, when using crypto.randomUUID() (available in modern browsers), the UUIDs are generated using a cryptographically secure random number generator.
What's the difference between UUID and GUID?
GUID (Globally Unique Identifier) is Microsoft's implementation of the UUID standard. They are essentially the same thing — both produce 128-bit unique identifiers in the same format.
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