UUID Generator
Generate UUID v4 (random) or v7 (time-ordered) in bulk, with format options. Nothing is uploaded — generation happens on your device.
UUID Generator
A UUID (universally unique identifier, also called a GUID) is a 128-bit value used to identify things without central coordination. RFC 9562 defines the current format and versions; RFC 4122, which it obsoletes, defined the string layout still shown today: five groups of hexadecimal digits separated by hyphens.
v4 vs v7
- Version 4 is generated from random bits, except the version and variant digits.
- Version 7 begins with a 48-bit Unix timestamp in milliseconds, then random bits. Because the timestamp comes first, v7 UUIDs sort in time order, which suits database keys.
- The version digit is the first character of the third group; the variant digit is the first character of the fourth group.
Frequently asked questions
Which UUID versions does this generate?
It generates version 4 (random) and version 7 (time-ordered) UUIDs, both defined in RFC 9562.
Is anything uploaded?
No. Generation uses your browser's built-in cryptographic random source and stays on your device.
What is the difference between v4 and v7?
A v4 UUID is built from random bits. A v7 UUID starts with a 48-bit Unix timestamp in milliseconds, so v7 UUIDs sort in time order while staying unique.
What do the version and variant digits mean?
In the canonical string, the first character of the third group encodes the version, and the first character of the fourth group encodes the variant (the RFC 4122/9562 layout).
Can I change the format?
Yes. You can output upper case, remove the hyphens, or wrap the value in braces.
Are these UUIDs safe to use as secrets?
No. A UUID is an identifier for uniqueness, not a secret; do not use it as a password, token or key.
Related: the text case converter, JSON formatter, or browse every browser-only tool on the all tools page.