GUID generator

GUIDs and UUIDs

A GUID (globally unique identifier) is Microsoft's name for a UUID: the same 128-bit value, written as 32 hex digits in groups of 8-4-4-4-12. Windows, COM, .NET, SQL Server's uniqueidentifier and Azure all use them to identify objects without a central registry. Microsoft tools usually print them in uppercase, and the Windows registry and Visual Studio project files wrap them in braces: {3F2504E0-4F89-41D3-9A0C-0305E82C3301}.

The GUIDs here are version 4: 122 random bits from your browser's cryptographic generator, the same kind Guid.NewGuid() returns in .NET.

Worked example

In C#, Guid.NewGuid().ToString("B").ToUpper() gives the braces format, ToString("D") the hyphenated form, and ToString("N") the 32 digits without hyphens. Pick the matching format above and paste the result straight into code, a .csproj file or an SQL INSERT.

Sequential GUIDs

Random GUIDs as clustered SQL Server keys cause page splits. For keys, consider time-ordered UUID v7, available in .NET 9 as Guid.CreateVersion7() and on the UUID generator page.

For each GUID the page draws 16 bytes from crypto.getRandomValues, the browser's cryptographically secure random source, sets the version bits to 4 and the variant bits to the RFC 9562 value, and formats the result: uppercase with hyphens, with braces, lowercase or without hyphens. GUIDs are created only in your browser when the page loads and each time you click Generate. None are stored or sent anywhere.