UUID Generator v4 / v1

Generate UUIDs in v4 and other versions.

Generate Multiple

How to use our UUID generator

Our UUID generator is an easy-to-use tool that allows you to generate one or more Universally Unique Identifiers (UUIDs) using either v4 or v1 versions. Simply click the "Generate UUID v4" button to generate a new UUID v4.

You can also generate multiple UUIDs at once by clicking the"Generate UUID v4" button under the "Generate Multiple" section. This will generate 10 UUIDs and display them in a list. We recommend trying both v4 and v1 to see how they differ - you'll notice how v1 UUIDs are deterministic and v4 UUIDs are random.

What is UUID

UUID stands for Universally Unique Identifier. It is a 128-bit number used to uniquely identify some object or entity on the internet. Depending on the specific mechanisms used, a UUID is either guaranteed to be different or is, at least, extremely likely to be different from any other UUID generated until 3400 A.D.

UUIDs are widely used in software development, particularly when it's necessary to uniquely identify something in a system without significant central coordination. Here are a couple of examples:

  • Databases: UUIDs can be used to generate unique identifiers for items in a database. This allows the database to ensure that all data is uniquely identifiable, which is particularly useful for distributed systems where it might not be easy to guarantee uniqueness otherwise.
  • File systems: Many file systems generate UUIDs when a file is created to make sure that each file can be uniquely identified.
  • Web applications: UUIDs can be used to generate unique identifiers for users, sessions, and other entities in a web application.
  • And any other system where it is necessary to uniquely identify something, but the ID doesn't need to be human-readable.

UUID Versions

There are several versions of UUID, each generated in different ways:

  • UUID v1: Generated using a host ID, sequence number, and the current time.
  • UUID v3: Generated using MD5 hashing and a namespace (which is also a UUID) and a name (a sequence of characters).
  • UUID v4: Generated using a random or pseudo-random number.
  • UUID v5: Generated using SHA-1 hashing and a namespace (which is also a UUID) and a name (a sequence of characters).

You can read more about UUIDs on Wikipedia.

Our UUID generator tool uses UUID v4 by default, but you can also generate UUID v1 by clicking the "Generate UUID v1" button.

Note: While each generated UUID is not guaranteed to be unique, the total number of unique keys (2^122 or 5.3x10^36) is so large that the probability of the same number being generated randomly twice is nearly zero. You can read our article for more information about the uniqueness of UUIDs.