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GUID Generator

Generate random GUIDs (UUID version 4) for .NET, SQL Server, Windows development and anywhere else a globally unique identifier is needed. Choose uppercase, curly braces or hyphen-free formats to match your codebase style.

GUID options

Cryptographically random version 4 IDs.

Format
Press Generate GUIDs.

Everything runs locally. Nothing is sent to any server.

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GUID vs UUID

GUID (globally unique identifier) is Microsoft's name for the same 128-bit format the rest of the world calls a UUID. A version 4 GUID fills 122 bits with cryptographic randomness, sets the version nibble to 4 and the variant bits to RFC 4122. .NET's Guid.NewGuid(), SQL Server's NEWID() and this tool all produce the same format.

Formatting options

Different ecosystems prefer different spellings: .NET and Windows APIs often use uppercase with braces like {3F2504E0-4F89-11D3-9A0C-0305E82C3301}, SQL Server accepts plain lowercase, and compact systems strip the hyphens to 32 hex characters. The format checkboxes reshape the same random bytes without changing the underlying value.

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GUID Generator FAQs

Are generated GUIDs really unique?
With 122 random bits there are 5.3 x 10^36 possible values, so the chance of a collision is negligible even when generating billions. You can treat every GUID as unique without a central registry.
Should GUIDs be uppercase or lowercase?
Both are valid and equivalent. .NET conventions favor uppercase with braces, while web APIs and JSON payloads usually use lowercase. Pick the style your codebase already uses.
Can I use a GUID as a database primary key?
Yes, SQL Server's uniqueidentifier type is built for it. Note that random GUIDs fragment clustered indexes; if insert speed matters, consider sequential GUIDs or UUID v7 instead.
Is it safe to expose GUIDs in URLs?
GUIDs are not secrets. They are unpredictable, which stops casual guessing, but anyone who sees one can use it, so still enforce authorization on the server side.
How do I generate a GUID in C#?
Call Guid.NewGuid().ToString() in C#. In SQL Server use NEWID(), in PowerShell use [guid]::NewGuid(), and in JavaScript use crypto.randomUUID(). This page is handy when you need a few without opening a code editor.
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