LASTINROW

LASTINROW(rgeInput)
Returns the last cell that contains data in a particular row.

REMARKS
Public Function LASTINROW( _

Public Function LASTINROW( _ 
        rngInput As Range) _ 
        As Variant 

Dim WorkRange As Range 
Dim i As Integer 
Dim CellCount As Integer 

    Application.Volatile 
    Set WorkRange = rngInput.Rows(1).EntireRow 
    Set WorkRange = Intersect(WorkRange.Parent.UsedRange, WorkRange) 
    CellCount = WorkRange.Count 
    For i = CellCount To 1 Step -1 
        If Not IsEmpty(WorkRange(i)) Then 
            LASTINROW = WorkRange(i).Value 
            Exit Function 
        End If 
    Next i 
End Function 

For instructions on how to add this function to a workbook refer to the page under Inserting Functions