UUID Generator (v4)

A UUID is a 128-bit universally unique identifier, usually written as 32 hex digits in five hyphen-separated groups shaped 8-4-4-4-12. It is also called a GUID and is used to label records, files and objects without a central authority handing out numbers.

Version 4 UUIDs are generated from random numbers. The 13th hex digit is fixed to 4 to mark the version, and the 17th digit is 8, 9, a or b to mark the variant. The remaining 122 bits are random, which is what makes each value unpredictable.

Practically, yes. With 122 random bits the chance of two v4 UUIDs colliding is vanishingly small even across billions of values. This tool also keeps every ID within a single batch distinct.

They come from your device's cryptographic random source through crypto.randomUUID, so they are unpredictable. UUIDs make great identifiers but are not secret keys, so never use one as a password, session token or API secret.

Yes. Turn on Uppercase for capital hex digits, and turn off Hyphens to get a 32 character string with no dashes. The two options combine, so you can produce an uppercase, dashless value in one click.

Between 1 and 1000 per batch. Values below 1 are treated as 1 and anything above 1000 is capped at 1000, so the output box and download stay manageable.

They are the same 128-bit format. GUID is the name Microsoft uses, while UUID is the term in the IETF standard. A value from this tool is valid under both names.

Yes. The download button writes the current batch, one UUID per line, to a plain text file named uuids.txt that you can import elsewhere or keep as a record.

No. Every UUID is created locally in your browser, so the values never leave your device and nothing is logged.