UUID Generator
Generate UUIDs (GUIDs) in various formats. Free online UUID generator.
Frequently Asked Questions
What is a UUID?
A UUID (Universally Unique Identifier), also known as GUID (Globally Unique Identifier), is a 128-bit identifier that is virtually guaranteed to be unique. UUIDs are represented as 32 hexadecimal digits separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
What is UUID v4?
UUID v4 is the most common version, where all bits except the version and variant bits are randomly generated. This means the probability of generating two identical UUIDs is astronomically low โ approximately 1 in 2.71 ร 10^36.
Are UUIDs really unique?
Yes, in practice. The number of possible UUID v4 values is 2^122 (about 5.3 ร 10^36). Even if you generated 1 billion UUIDs every second for 85 years, the probability of a collision would still be essentially zero.
What is a Nil UUID?
A Nil UUID is a special UUID where all 128 bits are zero: 00000000-0000-0000-0000-000000000000. It's sometimes used as a placeholder or default value in databases and APIs.
Where are UUIDs used?
UUIDs are widely used in software development for: database primary keys, distributed systems identifiers, file names, session tokens, API keys, and any scenario where you need a unique identifier without central coordination.
Is this tool free and private?
Yes, completely free with no sign-up required. All UUID generation happens in your browser using the native Web Crypto API. No data is sent to any server.