UUID generator
This UUID generator makes random version 4 UUIDs, 128-bit IDs written like 3f2b9c1e-8a4d-4f6b-9c2e-1d7a5b3e0f48. Developers use them as database keys, request IDs and test data when each ID must be unique without a central counter.
- Runs in your browser
- Free, no account needed
- Copy or download the result
Result
Example
6a15d8f6-e330-483d-a625-f0990602b4ab
How to use the uuid generator
- Leave the input box empty. This tool does not read it.
- Enter a value in Number of UUIDs, 1 to 100.
- Choose Letter case: Lowercase or Uppercase, then press Run.
- Copy result or Download the list, which has one UUID per line.
How it works
Each UUID starts as 16 bytes from crypto.getRandomValues, the browser's cryptographic random generator.
The version and variant bits are set as the UUID standard requires, so the third group always starts with 4 and the fourth group with 8, 9, a or b.
The count must be a whole number from 1 to 100. Decimals, negative numbers and blank values are rejected.
Any text in the input box is ignored, and each press of Run makes a fresh set.
Everything runs in your browser. Your input is not uploaded or stored.
Questions and answers
Can two UUIDs ever be the same?
In theory, yes. A version 4 UUID has 122 random bits, so a repeat is extremely unlikely in normal use.
Should I use a UUID as a password or secret token?
It is better not to. These come from a cryptographic random source, but UUIDs are designed as identifiers, and many systems log or display them openly.
What is the difference between a UUID and a GUID?
GUID is the name Microsoft uses for the same 128-bit ID format. A version 4 UUID can be used where a random GUID is expected.
Are the UUIDs saved or sent anywhere?
No. They are created in your browser and only appear on your screen.