How to use the UUID Generator
- Choose version 4 or 7.
- Choose how many you need.
- Copy or download the list.
What does this tool do?
UUIDs are 128-bit identifiers that are practically guaranteed to be unique without a central registry. Version 4 is fully random. Version 7 (standardised in RFC 9562 in 2024) starts with a millisecond timestamp, so new IDs sort in creation order — which keeps database indexes efficient.
Randomness comes from the Web Crypto API, the same secure source browsers use for encryption.
Why use it?
- IDs for databases, files and test data.
- v7 for sortable primary keys.
- Validate and inspect existing UUIDs.
Example v4
3f2b9c1e-8a4d-4f6e-9b2a-7c1d5e8f0a3b — the “4” at the start of the third group marks the version.
Privacy
Everything you type is processed in your browser. Nothing you enter is sent to our servers or stored by us. There's no account to create and nothing to install.
Frequently asked questions
Can two UUIDs ever be the same?
In theory, yes; in practice, no. You'd need to generate about a billion v4 UUIDs per second for 85 years to reach a 50% chance of a single collision.
Should I use UUID v4 or v7 for database keys?
v7 is usually the better choice for primary keys. Because it starts with a timestamp, new IDs are stored in order, which keeps database indexes compact and fast. Use v4 when you don't want IDs to reveal when they were created.
Last reviewed by the M2Toolkit team.