Excel-DNA is an independent project to integrate .NET into Excel. With Excel-DNA you can make native (.xll) add-ins for Excel using C#, Visual Basic.NET or F#, providing high-performance user-defined functions (UDFs), custom ribbon interfaces and more. Your entire add-in can be packed into a single .xll file requiring no installation or registration.

Getting Started

If you are using a version of Visual Studio that supports the NuGet Package Manager (including Visual Studio 2019 Community Edition), the easiest way to make an Excel-DNA add-in is to:

  1. Create a new Class Library (.NET Framework) project in Visual Basic, C# or F#.
  2. Use the Manage NuGet Packages dialog or the Package Manager Console to install the Excel-DNA package:
PM> Install-Package ExcelDna.AddIn

3. Add your code (C#, Visual Basic.NET or F#):

using ExcelDna.Integration;

public static class MyFunctions
    [ExcelFunction(Description = "My first .NET function")]
    public static string SayHello(string name)
        return "Hello " + name;

4.  Compile, load and use your function in Excel:


The Excel-DNA NuGet Package installs the required files and configures your project to build an Excel-DNA add-in.

Alternatively, get the full Excel-DNA download from GitHub, and work through the Getting Started page. The download includes a step-by-step guide to making your first C# add-in, and more information is available on the Documentation page.

More Details

Excel-DNA is developed using .NET, and users have to install the freely available .NET Framework runtime. The integration is by an Excel Add-In (.xll) that exposes .NET code to Excel. The user code can be in text-based (.dna) script files (C#, Visual Basic or F#), or compiled .NET libraries (.dll). Excel-DNA supports both the .NET runtime version 2.0 (which is used by .NET versions 2.0, 3.0 and 3.5) and version 4 (used by all newer versions). Add-ins can target either generation of the runtime, and concurrent loading of both runtime versions into an Excel instance is supported.

Excel versions ’97 through 2019 can be targeted with a single add-in. Advanced Excel features are supported, including multi-threaded recalculation (Excel 2007+), registration-free RTD servers (Excel 2002+) and customized Ribbon interfaces (Excel 2007+). There is support for integrated Custom Task Panes (Excel 2007+), offloading UDF computations to a Windows HPC cluster (Excel 2010+), and for the 64-bit versions of (Excel 2010+).

Most managed UDF assemblies developed for Excel Services can be exposed to the Excel client with no modification. (Please contact me if you are interested in this feature.)

Since Excel-DNA uses the Excel C API, porting C/C++ add-in code based on the Excel XLL SDK is very easy. (No more XLOPERs!)

The Excel-DNA Runtime is free for all use, and distributed under a permissive open-source license that also allows commercial use.

Latest Releases

The current version is Excel-DNA 1.1, released on 29 June 2020. This release included various bug-fixes and further improvements to the NuGet package build integration. Excel-DNA 1.1 is expected to be the final version with support for older .NET (< 4.5) and Excel (< 2007) releases.