What this tool does
Choose how many UUIDs you want (1, 5, 10, 25 or 50), tick uppercase or no hyphens if you need them, and the list is generated straight away. Copy the list and paste it wherever you need it.
How to use it
- Choose how many UUIDs you want.
- Tick uppercase or no hyphens if you need them.
- Copy the list.
How they are generated
Each UUID is version 4, which means 122 of its 128 bits are random. In a modern browser the tool calls crypto.randomUUID(), which uses a cryptographically secure random number generator. If that function is not available, it falls back to building the UUID with Math.random(). Those fallback values have the right format but are not suitable where unpredictability matters.
Everything happens in your browser, and generated values are not stored.
When a v4 UUID is a good choice
- Unique IDs for records created on several systems at once
- Idempotency keys and request IDs
- File names that shouldn’t collide
- Test data
When it isn’t
A v4 UUID is random, so it sorts randomly. If you use it as a primary key in MySQL’s InnoDB, inserts land all over the index, which hurts performance on large tables. Time-ordered identifiers such as UUID v7 or ULIDs work better for that. This tool doesn’t generate those.
Also, a UUID is an identifier, not a secret. Don’t use one as a password or an access token.
Format notes
The default form is the usual 8-4-4-4-12 layout in lowercase, for example 3b241101-e2bb-4255-8caf-4136c566a962. Removing hyphens gives 32 hex characters, which some databases and APIs expect. “Uppercase” matches the format used by some Microsoft tools, which call them GUIDs.
Are these UUIDs truly random?
In current browsers they come from crypto.randomUUID, a secure random source. Very old browsers use a weaker fallback.
Can two generated UUIDs collide?
In practice no. With 122 random bits the chance is negligible for any realistic volume.
Is a UUID safe to use as a secret token?
No. It is built to be unique, not secret. Use a purpose-made random token for authentication.
Does it generate version 1 or version 7 UUIDs?
No. Only version 4.
How many UUIDs can I generate at once?
1, 5, 10, 25 or 50, chosen before you generate. Options let you use uppercase and remove the hyphens.