UUID Generator (v4)

About UUID Generator

Generate random UUIDs (Universally Unique Identifiers) for databases, APIs, and distributed systems. This tool uses the browser’s cryptographically secure random number generator.

Key Features

• UUID v4: Generates random UUIDs using crypto.randomUUID()
• Bulk Generation: Generate up to 100 UUIDs at once
• Copy Individual or All: Copy single UUIDs or all at once
• Hyphen Toggle: Show UUIDs with or without hyphens
• Uppercase/Lowercase: Format options for your use case
• Cryptographically Secure: Uses Web Crypto API for true randomness

Common Use Cases

• Generate database primary keys
• Create unique session identifiers
• Generate API request IDs
• Create unique filenames
• Distributed system identifiers

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information. The standard format is:

xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx

Where:

• x is a random hexadecimal digit (0-9, a-f)
• The 4 indicates UUID version 4 (random)
• y is one of: 8, 9, a, or b (variant bits)

UUID v4 Details

Version 4 UUIDs are randomly generated with 122 random bits. The probability of a collision is approximately:

• 1 in 2.71 quintillion for the first collision in 1 billion UUIDs
• Effectively impossible in practice for most applications

FAQ

Are these UUIDs truly unique? While not mathematically guaranteed, the probability of collision is so low that UUIDs are considered unique for practical purposes.

What’s the difference between UUID and GUID? They’re essentially the same. GUID (Globally Unique Identifier) is Microsoft’s term for UUID.

Can I use these UUIDs in databases? Yes! Many databases support UUID types. However, be aware that random UUIDs can impact index performance compared to sequential IDs.

Which format should I use? Most systems use lowercase with hyphens: 550e8400-e29b-41d4-a716-446655440000