GUID Generator for .NET and Windows

What is a GUID?

A GUID is Microsoft's common name for a UUID: a 128-bit identifier used by .NET, Windows, SQL Server, COM, and many other systems. The underlying identifier follows the same version and variant rules as a UUID, while GUIDs are often displayed with uppercase letters or surrounding braces.

This generator creates random version 4 identifiers with the browser's cryptographic random-number generator. Version and variant bits are set correctly, and the identifier never leaves your browser.

GUID formats

The same identifier can be displayed in several equivalent ways:

• Standard: 6F9619FF-8B86-D011-B42D-00C04FC964FF
• Braced: {6F9619FF-8B86-D011-B42D-00C04FC964FF}
• Compact: 6F9619FF8B86D011B42D00C04FC964FF
• Lowercase: 6f9619ff-8b86-d011-b42d-00c04fc964ff

Choose the representation required by your application. Formatting changes the text representation, not the identifier itself.

Version 4 and nil GUIDs

Version 4 GUIDs use random data and are the right default for most application identifiers. A nil GUID contains only zeros and is commonly used as an empty or unset value. It is not unique and should never be used as a new record identifier.

Usage notes

• Generate between 1 and 50 identifiers at a time.
• Copy one GUID or the complete list.
• Use a database uniqueness constraint even though accidental version 4 collisions are extraordinarily unlikely.
• Do not treat a GUID as a password, access token, or proof of authorization.

For conventional lowercase UUID output, use the dedicated UUID v4 Generator.