How to Sum Every Nth Row in Google Sheets

To sum every nth row in Google Sheets, you can use a combination of SUM and ARRAYFORMULA functions. Here's a step-by-step guide on how to do it.

1. Open your Google Sheet with the data you want to sum.
2. Choose a cell where you want the sum to appear (e.g., E1).
3. In that cell, enter the formula to sum every nth row. Replace "n" with the desired interval and "range" with the range of cells containing the data.

Formula:

=SUM(ARRAYFORMULA(IF(MOD(ROW(range)-ROW(INDEX(range,1,1)),n)=0,range,0)))

For example, if you want to sum every 3rd row in the range A1:A10, you would use the following formula:

=SUM(ARRAYFORMULA(IF(MOD(ROW(A1:A10)-ROW(A1),3)=0,A1:A10,0)))

4. Press Enter to apply the formula, and the sum of every nth row will appear in the chosen cell.

Example

Let's say you have the following data in column A (A1:A10):

10
20
30
40
50
60
70
80
90
100

You want to sum every 2nd row, so you would enter the following formula in cell E1:

=SUM(ARRAYFORMULA(IF(MOD(ROW(A1:A10)-ROW(A1),2)=0,A1:A10,0)))

After pressing Enter, cell E1 will display the sum of every 2nd row: 20 + 50 + 80 + 100 = 250.