UUID/GUID Generator

Create random version 4 UUIDs or GUIDs

UUID and GUID commonly name the same 128-bit identifier format; GUID is especially familiar in Microsoft tooling. Choose 1 to 100 values, set any display options, and select Generate UUIDs/GUIDs. Results can appear one per line, comma-separated, or as a JSON array. Changing a format option updates the current identifiers without generating replacements.

What a UUID is

A universally unique identifier is a 128-bit value commonly displayed as 32 hexadecimal digits in five hyphen-separated groups. UUIDs help label records without asking one central database for the next sequential number. They are useful in distributed applications, test fixtures, import files, client-generated objects, and public identifiers where predictable counters are undesirable.

UUID versus GUID

UUID is the standards-based name for a universally unique identifier. GUID, short for globally unique identifier, is the name Microsoft adopted for the same kind of 128-bit value. That history left two familiar terms in documentation, APIs, and database tools even though they usually describe compatible identifiers.

In everyday use, a UUID shown as 550e8400-e29b-41d4-a716-446655440000 can also be called a GUID. The canonical text representation is the same, so this generator's output works in fields labeled either UUID or GUID. Some platforms store or transmit parts of the underlying 16 bytes in a different order, however, so integrations using raw binary values should follow the receiving system's byte-order rules.

Version 4 format

This page generates random version 4 UUIDs. A typical value looks like 550e8400-e29b-41d4-a716-446655440000. The digit 4 in the version position identifies version 4, while designated variant bits describe the layout. The remaining bits come from a cryptographically strong random source supplied by the browser.

Choosing an output format

Keep hyphens for the conventional text form, or remove them when a destination expects 32 uninterrupted hexadecimal characters. Uppercase changes presentation only. Braces are common around GUIDs in some Microsoft contexts. Use line-separated output for columns and text files, comma-separated output for compact pasting, or a JSON array for code and structured data. Confirm the destination's accepted format before importing a large batch.

Worked example

Request three UUIDs when preparing sample database rows. Keep the default line-separated format to assign one unchanged string to each row's identifier field. If a development fixture needs JSON instead, select JSON array; the same three identifiers are reformatted as quoted array values rather than regenerated. Do not reuse one output for records that must remain distinct.

Uniqueness is probabilistic

Random UUIDs provide an enormous identifier space, making accidental collision extremely unlikely under ordinary generation volumes. “Universally unique” is practical shorthand, not a mathematical proof that duplication can never happen. Systems with strict integrity needs should still enforce a unique constraint and retry if an insertion reports a collision.

Security and privacy limits

UUIDs identify; they do not authenticate or authorize. A UUID is not a password, API secret, encryption key, session token, or proof of ownership. Do not expose sensitive data merely because its route contains an unguessable identifier. Generation stays in the browser and this page does not save outputs, but anything copied elsewhere follows that destination's privacy rules.