Sum every 4th column

[rplohocky]

Hello,
I have searched high and low to find a basic formula to add up every 4th column and every formula I have tried has failed. I am trying to add every 4th cell from each column. Example: Add C3+G3+K3+O3, etc. Can anyone provide a formula to do this?

The range starts at A3 through BS3. It can be an array if necessary.

 

[steve the fish]

See if this works:

=SUMPRODUCT(A3:BS3,--(MOD(COLUMN(A3:BS3)+1,4)=0))

 

[oldbrewer]

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
2.328576	0.723402	2.121525	14.09262	10.24788	7.973519	9.523228	14.21621	0.023632	14.681	8.685369	13.60021	2.273414	9.786615	16.93699	13.75881	12.89917
		aim - sum A3,e3,i3,m3,q3
2.328576				10.24788				0.023632				2.273414				12.89917
this 4 obtained by
=IF(ISERROR(MATCH(A1,$N$20:$N$24,0)),"",A3)
total is clearly then sum of a10:gz10)
													1
													5
													9
													13
													17

<colgroup><col span="18"></colgroup><tbody>
</tbody>

 

[oldbrewer]

1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
2.328576	0.723402	2.121525	14.09262	10.24788	7.973519	9.523228	14.21621	0.023632	14.681	8.685369	13.60021	2.273414	9.786615	16.93699	13.75881	12.89917
		aim - sum A3,e3,i3,m3,q3
2.328576				10.24788				0.023632				2.273414				12.89917
this 2.32 obtained by
=IF(ISERROR(MATCH(A1,$N$20:$N$24,0)),"",A3)
total is clearly then sum of a10:gz10)
													1
													5
													9
													13
													17

<colgroup><col span="18"></colgroup><tbody>
</tbody>

 

[BGY23]

Try this

Enter a blank row at column A. I cell C1 put a 1. In cell d1 enter if (c1=4,1,c1+1) copy it across the row.

In the cell where you want the sum enter =sumif(C1:BS1,4,C3:BS3). Change the range required.

 

[rplohocky]

See if this works:

=SUMPRODUCT(A3:BS3,--(MOD(COLUMN(A3:BS3)+1,4)=0))

Steve- This formula works great! Thank you and thanks to everyone else for the help!