UUID Generator
Generate cryptographically random UUID v4 identifiers in bulk, straight from your browser.
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0 UUIDs
What this tool does
Generates version 4 UUIDs — random 128-bit identifiers — in batches, formatted however your system expects them. Fresh values are generated the moment the page loads.
Where the randomness comes from
These come from crypto.randomUUID(), which draws on your operating system's cryptographically secure random number generator. That's the same source used for encryption keys, not the predictable Math.random() that some generators rely on.
Will they ever collide?
A v4 UUID has 122 random bits. You would need roughly 2.7 × 1018 of them before reaching a 50% chance of a single collision — generate a million per second and you'd wait around 85 years. For any real system, treat collisions as impossible and don't engineer around them.
UUID or GUID?
They're the same thing. GUID is Microsoft's name for the identical 128-bit format, so values from this tool work anywhere a GUID is expected. The {braces} format exists because some Microsoft tooling writes them that way.
FAQ
What is a UUID?
A UUID is a 128-bit identifier written as 36 characters, such as 3f2b8c4e-9d1a-4f6b-8e2c-7a5d9b0c1e3f. It is designed to be unique without any central coordination, so separate systems can each mint identifiers that will not collide.
Are these UUIDs actually random?
Yes. They come from crypto.randomUUID(), which draws on your operating system's cryptographically secure random number generator. They are version 4 UUIDs, with 122 bits of randomness.
Could two UUIDs ever be the same?
In theory yes, in practice no. With 122 random bits you would need to generate about 2.7 × 10^18 UUIDs before a 50% chance of a single collision. For any realistic workload the risk is not worth engineering around.
Are these generated on a server?
No. They are generated in your browser and never transmitted. That matters for identifiers: a UUID fetched from someone else's server is a value that someone else has seen.
What is the difference between a UUID and a GUID?
Nothing meaningful. GUID is Microsoft's name for the same 128-bit identifier format. The two terms are used interchangeably, and values are compatible.