What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit label used for information in computer systems. It allows distributed systems to uniquely identify information without significant central coordination.
The most common version, UUID v4, is generated using random numbers. The probability of duplication is virtually zero, making it the industry standard for primary keys in databases like MongoDB, PostgreSQL, and Cassandra.
Key Features
Cryptographically Secure
We use the Web Crypto API, not Math.random(), ensuring high-entropy randomness suitable for security keys.
Bulk Generation
Need 500 IDs for a mock database? Generate hundreds at once with a single click.
Custom Formatting
Toggle hyphens, uppercase/lowercase, or wrap in quotes/braces for SQL or JSON use.
100% Private
IDs are generated locally in your browser. We never see or store your data.
How to Use the UUID Generator
Get your unique IDs in seconds. Here is the workflow:
Set Quantity
Enter how many UUIDs you need (e.g., 1, 10, or 100). The default is 1.
Customize
Toggle options like "Uppercase", "Remove Hyphens", or "Add Quotes" based on your requirements.
Copy Results
Click "Generate" and then hit the Copy button to paste them into your code or database.
The Math Behind Uniqueness
Did you know? To have a 50% chance of a single collision (duplicate ID), you would need to generate 1 billion UUIDs per second for about 85 years. That is how secure Version 4 is.
Structure of a UUID
A standard UUID is a 36-character string (including hyphens) in the format 8-4-4-4-12:
- M: The version digit (4 for random UUIDs).
- N: The variant digit (8, 9, A, or B).
- x: Random hexadecimal digits (0-9, a-f).
Common Formatting Options
- Standard
Canonical format with hyphens. Most readable. Used in URLs and configs.
- No Hyphens
32 characters. Used to save storage space in databases (stored as BINARY(16)).
- Uppercase
Often required by legacy systems, older Windows applications, or specific GUID implementations.