Generate one or thousands of random version-4 UUIDs (GUIDs) with cryptographic randomness.
🔒 This tool runs entirely in your browser. Nothing you enter or upload is sent to our servers.
How to use the UUID Generator
- Choose how many UUIDs you need and the formatting options.
- Click Generate. The list appears below.
- Copy all with one click, or copy an individual line.
About this tool
A UUID (Universally Unique Identifier, called GUID on Windows) is a 128-bit value written as 32 hex digits in five groups: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx. Version 4 UUIDs are random: 122 bits of randomness make collisions practically impossible, so they’re safe to generate independently on many machines without coordination. They’re used as database keys, request IDs, file names and API tokens.
Frequently asked questions
What do the 4 and the y positions mean?
The 4 is the version number. The y position holds the variant bits and is always 8, 9, a or b for RFC 4122 UUIDs.
Can two generated UUIDs be the same?
The probability is astronomically small — you’d need to generate about a billion UUIDs per second for decades to reach a 50% chance of one duplicate.
Are these UUIDs secure enough for tokens?
They use crypto.getRandomValues(), so they are unpredictable. For security tokens, though, prefer a dedicated random token of 256 bits or more.