# Calculating monthly average from daily average (grouped by month)

I have a spreadsheet with three columns: one for dates, one for daily income and one for daily change rates.

I want to have a sum of all the daily income grouped by month as seen above. For that, on cell E2 I have the following formula:

``````=ArrayFormula({unique(text(A2:A,"MMMYY")),
sumif(text(A2:A,"MMMYY"),unique(text(A2:A,"MMMYY")),B2:B)})
``````

It works well. Now, I would like to calculate the monthly average from the daily average (grouped by month). This is what I tried:

``````=ArrayFormula({unique(text(A2:A,""MMMYY"")),
sumif(text(A2:A,""MMMYY""),
unique(text(A2:A,""MMMYY"")),B2:B), AVERAGEif(text(A2:A,""MMMYY""),
unique(text(A2:A,""MMMYY"")),C2:C)})
``````

It doesn't work, it gives out the following:

``````ErrorFunction ARRAY_ROW parameter 3 has mismatched row size. Expected: 4. Actual: 1.
``````

Edit: In the end, I found a way to make it work using query:

``````=query({ArrayFormula(EOMONTH(A2:A82,0
)),B2:B82,C2:C82},"Select Col1, Sum(Col2),avg(Col2) group by Col1 format Col1'MMM-YY'")
``````

Any ideas how to solve this without query?

Thanks!

``````=ArrayFormula({unique(text(A2:A,"MMMYY")),
What we actually do is `sum/count=average`