UUID Generator

What is a UUID?

A UUID (Universally Unique Identifier), also called a GUID (Globally Unique Identifier), is a 128-bit value used to uniquely identify information without needing a central authority to coordinate IDs. Version 4 UUIDs (the type this tool generates) are built almost entirely from random bits, making collisions astronomically unlikely even across millions of generated values. They're commonly used as database primary keys, API keys, session identifiers, and test fixtures.

How to use this tool

Set how many UUIDs you want to generate at once, optionally enable uppercase formatting or remove hyphens, and click Generate UUID. All UUIDs are generated locally in your browser using crypto.randomUUID(); nothing is sent to a server. Copy the results with the clipboard icon.

Common use cases

• Generating a primary key for a new database record without needing a central auto-increment counter.
• Creating a unique session token, request ID, or idempotency key for an API call.
• Producing test fixture IDs that won't collide with real production identifiers.
• Assigning a unique identifier to a file, device, or resource across distributed systems.

Frequently asked questions

What's the difference between a UUID and a GUID?

None in practice. GUID is Microsoft's name for the same 128-bit identifier format defined by the UUID standard (RFC 4122); the terms are used interchangeably.

How likely is it that two generated UUIDs collide?

For version 4 (random) UUIDs, effectively never in practice. There are 2^122 possible values, so even generating a billion UUIDs per second, you'd need billions of years before a collision became statistically likely.

Can I use a UUID as a database primary key?

Yes, and it's common practice, especially in distributed systems where multiple servers need to generate IDs independently without coordinating. The trade-off is that UUIDs take more storage than an integer and don't sort in insertion order like an auto-increment ID does.

Are these UUIDs generated on your server?

No. Every UUID is generated locally in your browser using the Web Crypto API's crypto.randomUUID(); nothing is sent to us.