About this tool
A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier) in Microsoft environments, is a 128-bit label used to uniquely identify information in computer systems. The standard format (RFC 4122) is 36 characters: 8-4-4-4-12 hex digits separated by hyphens, like 123e4567-e89b-12d3-a456-426614174000.
UUID Version 4 uses random or pseudo-random numbers for generation. It does not expose any information about the generating system or timing, making it suitable for distributed systems where coordination is impossible. The probability of collision with just 1 billion UUIDs is about 1 in 2^64 (roughly 1 in 18 quintillion).
Our UUID Generator uses the Web Cryptography API (window.crypto.getRandomValues) — the cryptographically secure random number generator built into every modern browser. This is superior to Math.random() which is deterministic and unsuitable for unique ID generation. All generation happens locally — no IDs are ever transmitted or stored.
Practical Usage Examples
Database primary key
Use UUID as primary key for distributed database records.
Generated: 6ba7b810-9dad-11d1-80b4-00c04fd430c8
SQL: INSERT INTO users (id, name) VALUES ('6ba7b810...', 'John')API request tracking
Assign unique ID to each API request for logging and debugging.
Request-ID: f47ac10b-58cc-4372-a567-0e02b2c3d479
Logs: [f47ac10b...] Request started...File naming
Generate unique filenames to prevent overwrites in uploads.
Original: photo.jpg
Stored: 8f3e4a2b-1c9d-4e6f-a0b1-2d3e4f5a6b7c.jpgStep-by-Step Instructions
Select the number of UUIDs to generate (1 to 10,000).
Choose the output format: Hyphenated (standard), Compact, Braced ({uuid}), or URN format.
Click "Generate" to create your UUIDs.
Review the list and use Copy to copy all UUIDs to clipboard.
Download the results as a text file if needed.
Core Benefits
Uses cryptographically secure random generation (window.crypto.getRandomValues).
Supports bulk generation up to 10,000 UUIDs at once.
Multiple output formats: hyphenated, compact, braced, URN.
100% client-side — generated IDs never leave your browser.
Free, no signup, works offline after first load.
Frequently Asked Questions
UUID v1 includes the MAC address and timestamp, which can reveal information about the generating system and time. UUID v4 uses random numbers, producing truly unpredictable IDs with no identifiable metadata. v4 is preferred for most applications.
A UUID v4 has 122 random bits (16 bytes minus 6 variant/version bits). The probability of collision after generating 1 billion UUIDs is about 1 in 18 quintillion — effectively zero for any practical application. With 3.4 × 10^38 possible values, you can safely use UUIDs as primary keys in databases.
Yes. We use window.crypto.getRandomValues, which is a cryptographically secure random number generator (CSPRNG) provided by the browser. This is the same source browsers use for generating session tokens and encryption keys.
URN (Uniform Resource Name) format prefixes a UUID with "urn:uuid:" followed by the standard hyphenated format. Example: "urn:uuid:123e4567-e89b-12d3-a456-426614174000". This is used in some XML and standards-compliant contexts.
Yes. UUIDs are widely used as primary keys, especially in distributed systems and microservices where centralized ID generation is impractical. They are larger than auto-increment integers (16 bytes vs 4-8 bytes) but provide global uniqueness without coordination.