UUID Generator
Generate RFC-4122 version 4 UUIDs singly or in bulk, using the browser's cryptographic random source.
How to use the UUID Generator
- Choose how many UUIDs you need.
- Generate them.
- Copy one or the whole list.
About the UUID Generator
A version 4 UUID is 122 random bits, which makes collisions so improbable that separate systems can generate identifiers independently without coordination. That is why they are the default for distributed systems and offline-capable clients. They are not sequential, so using one as a clustered primary key can hurt database write performance — a common reason teams reach for UUIDv7 instead.
Frequently asked questions
What is a version 4 UUID?
A 128-bit identifier where 122 bits are random, defined by RFC 4122 — the standard random UUID format.
Can two UUIDs collide?
Theoretically yes, practically no. The probability is negligible even across billions of generated values.
Are these cryptographically random?
Yes, they use the browser's crypto random source rather than Math.random.
Are UUIDs guaranteed to be unique?
Not guaranteed, but the odds are negligible. A version 4 UUID has 122 random bits, so you would need to generate billions per second for decades before a collision became likely. For database keys and file names that is unique enough in practice.
Is a UUID the same as a GUID?
Yes — GUID is Microsoft's name for the same 128-bit identifier. These are version 4 UUIDs generated from the browser's cryptographic random source, so they are safe to use as database keys or request identifiers.
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Runs entirely in your browser — nothing you enter is uploaded. Last reviewed and updated .