How to reference Microsoft.Office.Interop.Excel dll?

Use NuGet (VS 2013+):

The easiest way in any recent version of Visual Studio is to just use the NuGet package manager. (Even VS2013, with the NuGet Package Manager for Visual Studio 2013 extension.)

Right-click on "References" and choose "Manage NuGet Packages...", then just search for Excel.

---

VS 2012:

Older versions of VS didn't have access to NuGet.

• Right-click on "References" and select "Add Reference".
• Select "Extensions" on the left.
• Look for Microsoft.Office.Interop.Excel.
  (Note that you can just type "excel" into the search box in the upper-right corner.)

---

VS 2008 / 2010:

• Right-click on "References" and select "Add Reference".
• Select the ".NET" tab.
• Look for Microsoft.Office.Interop.Excel.

You can also try installing it in Visual Studio via Package Manager.

Run Install-Package Microsoft.Office.Interop.Excel in the Package Console. This will automatically add it as a project reference.

Use is like this:

Using Excel=Microsoft.Office.Interop.Excel;