UUID Generator

Generate random UUIDs (v4) instantly

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What is a UUID?

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit number used to uniquely identify information in computer systems. The standard format is 32 hexadecimal digits grouped as xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

UUIDs were originally created for the Apollo Network Computing System and later standardized by the Open Software Foundation (OSF) as part of the Distributed Computing Environment (DCE).

UUID Versions

  • v1: Time-based — uses timestamp and MAC address
  • v3: Name-based — uses MD5 hash of namespace + name
  • v4: Random — uses cryptographically secure random numbers (most common)
  • v5: Name-based — uses SHA-1 hash of namespace + name

This tool generates UUID v4, which is the most widely used version in modern applications.

How to Use

  1. Set the number of UUIDs to generate (1 to 100)
  2. Choose uppercase or lowercase format
  3. Click “Generate” or press Ctrl+Enter
  4. Copy the results

Common UUID Use Cases

  • Database primary keys: UUIDs avoid the need for sequential ID generation in distributed databases
  • API identifiers: Expose UUIDs instead of sequential IDs to prevent enumeration attacks
  • Distributed systems: Generate unique IDs without coordination between nodes
  • File naming: Ensure unique filenames for uploads
  • Session tokens: Create unique session identifiers

Frequently Asked Questions

What is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. Also known as GUID (Globally Unique Identifier), UUIDs are formatted as 32 hexadecimal digits displayed in five groups separated by hyphens: 8-4-4-4-12.

What is UUID v4?

UUID v4 is the most commonly used version. It generates UUIDs using random or pseudo-random numbers. 122 of the 128 bits are randomly generated, making collisions extremely unlikely (1 in 2^122).

Are UUIDs truly unique?

While not mathematically guaranteed to be unique, the probability of generating two identical UUID v4 values is astronomically low — approximately 1 in 5.3 x 10^36. For practical purposes, they are considered unique.

When should I use UUIDs?

UUIDs are ideal for database primary keys, distributed systems, session identifiers, file names, and any scenario where you need a unique identifier without a central authority.

Is my data safe?

Yes. UUIDs are generated entirely in your browser using the Web Crypto API. Nothing is sent to any server.