UUID / GUID Generator

Instantly generate version 4 (random) Universally Unique Identifiers.

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Generating Truly Unique Identifiers for Modern Apps

In software development, databases, and network engineering, identifying objects uniquely is a critical task. A Universally Unique Identifier (UUID), also known as a Globally Unique Identifier (GUID), is a 128-bit number used to ensure uniqueness across systems without requiring a central authority. Our Free UUID Generator provides an instant, secure way to generate these IDs for your projects.

Understanding UUID Version 4

There are several versions of UUIDs, but Version 4 is the most widely used in modern applications. Unlike Version 1 (which uses the computer's MAC address and time), Version 4 is generated using **random numbers**. This makes it incredibly secure and privacy-friendly, as it doesn't leak any information about the device that created it.

Collision Probability: Is it really unique?

A UUID consists of 32 hexadecimal digits. The number of possible Version 4 UUIDs is approximately **5.3 x 10^36** (that's 5 followed by 36 zeros!). To put this in perspective, if you generated one billion UUIDs every second for the next 100 years, the probability of creating a duplicate would still be practically zero. This is why they are trusted for critical systems like database primary keys and session tokens.

Common Applications

  • Database Primary Keys: Use UUIDs instead of auto-incrementing integers to make merging databases from different servers seamless.
  • Session Tokens: Securely identify user sessions in web applications.
  • Transaction IDs: Assign a unique reference number to every financial or data transaction.
  • API Keys: Generate random strings for authentication in your custom APIs.

Standard Format:

A standard UUID is represented by 32 hexadecimal digits, displayed in five groups separated by hyphens, in the form 8-4-4-4-12 (e.g., 123e4567-e89b-12d3-a456-426614174000).

Frequently Asked Questions

Essentially, no. **GUID** is Microsoft's implementation of the **UUID** standard. While there are some technical nuances in how different platforms generate them, they serve the same purpose and follow the same 128-bit format.

While UUID v4 is based on random numbers, it is not designed to be a replacement for high-security cryptographic keys. For things like SSL certificates or password hashing, you should use specialized cryptographic libraries.

Yes. The generation happens entirely within your browser using JavaScript's `crypto.getRandomValues()` API. We do not store or track any of the UUIDs you generate.