Calculate Moving Average in Excel - excel

Question

I want to calculate a moving average of the last, say 20, numbers of a column. A problem is that some of the cells of the column may be empty, they should be ignored. Example:
A
175
154
188
145
155
167
201
A moving average of the last three would be (155+167+201)/3. I've tried to implement this using average, offset, index, but I simply don't know how. I'm a little bit familiar with macros, so such a solution would work fine: =MovingAverage(A1;3)
Thanks for any tips or solutions!

Answer 1

{=SUM(($A$1:A9)*(ROW($A$1:A9)>LARGE((ROW($A$1:A9))*(NOT(ISBLANK($A$1:A9))),3+1)))/3}
Enter this with control+shift+enter to make it an array formula. This will find the latest three values. If you want more or less, change the two instances of '3' in the formula to whatever you want.
LARGE((ROW($A$1:A9))*(NOT(ISBLANK($A$1:A9))),3+1)
This part returns the 4th highest row number of all the cells that have a value, or 5 in your example because rows 6, 8, and 9 are the 1st through 3rd highest rows with a value.
(ROW($A$1:A9)>LARGE((ROW($A$1:A9))*(NOT(ISBLANK($A$1:A9))),3+1))
This part returns 9 TRUEs or FALSEs based on whether the row number is larger than the 4th largest.
($A$1:A9)*(ROW($A$1:A9)>LARGE((ROW($A$1:A9))*(NOT(ISBLANK($A$1:A9))),3+1))
This multiplies the values in A1:A9 by those 9 TRUEs or FALSEs. TRUEs are converted to 1 and FALSEs to zero. This leaves a SUM function like this
=SUM({0;0;0;0;0;155;0;167;201})/3
Because all the values above 155 don't satisfy the row number criterion, the get multiplied by zero.

Answer 2

If you are going to use a UDF it will only recalculate correctly when you change the data if the parameters include all the range of data you want to handle.
Here is a moving average UDF that handles entire columns and contains some error handling. You can call it using by entering the formula =MovingAverage(A:A,3) into a cell.
Function MovingAverage(theRange As Range, LastN As Long) As Variant
Dim vArr As Variant
Dim j As Long
Dim nFound As Long
Dim dSum As Double
On Error GoTo Fail
MovingAverage = CVErr(xlErrNA)
'
' handle entire column reference
'
vArr = Intersect(Application.Caller.Parent.UsedRange, theRange).Value2
If IsArray(vArr) And LastN > 0 Then
For j = UBound(vArr) To 1 Step -1
' skip empty/uncalculated
If Not IsEmpty(vArr(j, 1)) Then
' look for valid numbers
If IsNumeric(vArr(j, 1)) Then
If Len(Trim(CStr(vArr(j, 1)))) > 0 Then
nFound = nFound + 1
If nFound <= LastN Then
dSum = dSum + CDbl(vArr(j, 1))
Else
Exit For
End If
End If
End If
End If
Next j
If nFound >= LastN Then MovingAverage = dSum / LastN
End If
Exit Function
Fail:
MovingAverage = CVErr(xlErrNA)
End Function

Answer 3

Just a quick solution:
Supposing your numbers are on the cells A2:A10, put in B10 the following formula:
=IF(COUNT(A8:A10)=3,AVERAGE(A8:A10),IF(COUNT(A7:A10)=3,AVERAGE(A7:A10),"too many blanks"))
Dragging up the formula you get the moving average
If there is the possibility of two consecutive blank you could nest another if, more than that and this solution became too complicated

Answer 4

I have written a short script in VBA. Hopefull it does what you want. Here you are:
Function MovingAverage(ByVal r As String, ByVal i As Integer) As Double
Dim rng As Range, counter As Long, j As Integer, tmp As Double
Set rng = Range(r)
counter = 360
j = 0
tmp = 0
While j < i + 1 And counter > 0
If Len(rng.Offset(j, 0)) > 0 Then
tmp = tmp + rng.Offset(j, 0).Value
End If
j = j + 1
counter = counter - 1
Wend
MovingAverage = CDbl(tmp / i)
End Function
1) I have set limit to 360 cells. It means that the script will not look for more than 360 cells. If you want to change it then change the initial value of counter.
2) The script returns not rounded average. Change the last row to
MovingAverage = Round(CDbl(tmp / i),2)
3) The use is just like you wanted, so just type =MovingAverage("a1";3) into the cell.
Any comments are welcome.