title: Built-in Excel functions in a managed UDF for Excel Services
body: <p>I’m thinking of moving a set of VBA functions to VB.Net with the objective using them to perform server-side calculations in Excel Services and Sharepoint. My understanding is that I need to create a managed UDF for this.</p>
  
  <p>My question relates to the built-in Excel functions I’ve been using in VBA:</p>
  
  <pre><code>Application.Sum
  Application.SumSq
  Application.Count
  Application.Average
  Application.StDev
  Application.Skew
  Application.Kurt
  Application.Min
  Application.Max
  Application.NormSInv
  Application.TInv
  Application.TTest
  Application.VarP
  Application.MDeterm
  Application.MInverse
  Application.MMult
  Application.Transpose
  Application.LinEst
  Application.Index
  Application.WorksheetFunction.RSq
  Application.WorksheetFunction.Correl
  </code></pre>
  
  <p>Will Excel Services pick up on the fact these are native Excel functions? If so, what do I need to do in .Net to make Excel Services aware that these functions are native to Excel? Any worked examples would be greatly appreciated if this is possible.</p>
  
  <p>Or would I be better of using .Net alternatives to these functions? If so, is there a source you can point me to which explains the mapping of native Excel functions to VB.Net functions?</p>
  
  <p>Or am I forced to re-write these standard functions as custom functions?</p>
  
  <p>Many thanks in advance for your help.</p>
  
  <p>Regards,
  JK</p>