UUID generator: v4 and v7
Random v4 or time-sorted v7 UUIDs, generated on your device, with copy and download.
- Runs on your device
- No sign-up
- Works offline after a visit
How to generate a UUID
- Choose version 4 for random IDs, or version 7 for IDs that sort by time.
- Set the count, then tick uppercase, no hyphens or braces if your code needs them.
- Copy all or download the list. Paste any UUID under Inspect to read its version and time.
Questions
What is the difference between UUID v4 and v7?
Version 4 is random apart from the version and variant bits. Version 7 begins with the Unix time in milliseconds, so IDs made later sort later, which suits database keys that are indexed in order.
Are the generated UUIDs unique?
Random v4 values are unique in practice, since 122 of their bits are random. The generator uses crypto.randomUUID or crypto.getRandomValues, the browser’s cryptographic random source. Within one page, v7 IDs count up inside each millisecond, so they never repeat.
Can I use a UUID as a password?
No. A UUID is an identifier, not a secret, and a v7 UUID shows when it was made. Use a password manager’s generator for passwords and access tokens.
Where does the time in a v7 UUID come from?
The first 48 bits hold the Unix time in milliseconds, taken from your device clock. Inspect turns those bits back into an ISO date and time in UTC.