GUID V4 - Random-Based Identifier (Recommended)
GUID v4 is the most widely used random-based identifier. Learn about its structure, collision probability, advantages and why it is recommended for general-purpose applications.
How to Generate GUIDs in C#
Generate GUIDs in C# with Guid.NewGuid() for random values and Guid.CreateVersion7() on .NET 9 or newer when you want timestamp ordering plus randomness.
Recommendation: use GUID v4 for general-purpose random IDs. Use GUID v7 when you want better insertion locality and time ordering in logs or databases.
How to generate GUID v4 in C#
The built-in Guid.NewGuid() API is the standard way to generate a random GUID in .NET.
using System;
Guid id = Guid.NewGuid();
Console.WriteLine(id);
// Example: d0c5d3e8-4a52-4a65-aada-2b9d88f0d4dcHow to generate GUID v7 in C#
.NET 9 and later can generate a time-ordered GUID directly with Guid.CreateVersion7(). If you target an older runtime, use a library that supports RFC 9562 v7.
using System;
Guid id = Guid.CreateVersion7();
Console.WriteLine(id);
// Example: 0195d9f7-f4f2-7c44-bdb3-6f5de9a1a6f0Native support notes
- C# and .NET natively expose GUID generation APIs instead of separate UUID terminology.
- GUID v4 is widely available through
Guid.NewGuid(). - GUID v7 is built in on .NET 9 and later.
- Other UUID versions are not first-class everyday APIs in the base library.
Practical notes
Frequently Asked Questions
Yes. In .NET the native name is GUID, but the underlying 128-bit identifier format matches the UUID standards.
Guid.CreateVersion7() is available on .NET 9 and later. Use Guid.NewGuid() for random identifiers everywhere, and use a v7-capable library if you need time-ordered IDs on older runtimes.Learn more
These articles expand on related concepts, formats and practical considerations.