Here's one way.

Let's say your data is in A1:F20000. Click in cell G1 and type this
formula

=IF(MOD(ROW(),48)=0,"YES","NO")

Copy column G and paste values. Now column G has "YES" every 48th
row. In column H put

=IF(G1="YES",AVERAGE(A1:G1),"")

Again, copy and paste values if you want the hard-coded data to stick.


HTH,
JP

On Nov 16, 4:52 pm, akoskelo
wrote:
Hi. I have a huge spreadsheet (~20,000 rows). I need to average every 48 rows
into one value. Is there a quick and easy way to do this without scrolling
through all 20,000 rows and copy-pasting the "average" function every 48th
row?

Thank you.