v1 uses timestamp and MAC — predictable. v4 is fully random, recommended for most modern use cases.

Can two UUIDs be equal?

Theoretically yes, practically no: collision probability is ~1 in 2¹²². You'd have to generate billions per second for decades to see one.

Are UUIDs generated on my device?

Yes, via crypto.getRandomValues. Nothing is sent to a server.

Generators

UUID generator

Generate one or more random UUID v4 identifiers. Multiple export formats: lowercase, uppercase, no dashes, braces.

Quantity

Format

Results

How to use this tool

A UUID (Universally Unique Identifier) is a 128-bit identifier, statistically unique. Version 4 (used here) is fully random: the collision probability is negligible over billions of UUIDs. Useful for database IDs, transaction keys, unique filenames.

Concrete examples

f47ac10b-58cc-4372-a567-0e02b2c3d479 (standard)
F47AC10B58CC4372A5670E02B2C3D479 (no dashes, upper)
{f47ac10b-58cc-4372-a567-0e02b2c3d479} (braces)

Frequently asked questions

Why v4 not v1?: v1 uses timestamp and MAC — predictable. v4 is fully random, recommended for most modern use cases.
Can two UUIDs be equal?: Theoretically yes, practically no: collision probability is ~1 in 2¹²². You'd have to generate billions per second for decades to see one.
Are UUIDs generated on my device?: Yes, via crypto.getRandomValues. Nothing is sent to a server.