Hi
It would help if you post the udf. I'm sure there are several udf's with that name available on the web.
Function Countcolour(rng As Range, colour As Range) As Long
Dim c As Range
Application.Volatile
For Each c In rng
If c.Interior.ColorIndex = colour.Interior.ColorIndex Then
Countcolour = Countcolour + 1
End If
Next
End Function
Just pass the range you indicated encased in a set of parentheses...
=Countcolour((B1:M1,C2:M2,D3:M3,E4:M4,F5:M5,G6:M6,H7:M7,I8:M8,J9:M9,K10:M10,L11:M11,M12),A2)