If white is the default fill color you only need to test for gray and blue.

Select the range of cells in question. Assume it's A6:An
Goto the menu FormatConditional Formatting
Condition 1 (gray)
Select the Formula Is option
Enter this formula in the box on the right:

=AND(MOD(ROWS(A$6:A6),24)=9,MOD(ROWS(A$6:A6),24)< =16)

Click the Format button
Select a GRAY fill color
OK

Click the Add button

Condition 2 (blue)
Select the Formula Is option
Enter this formula in the box on the right:

=OR(MOD(ROWS(A$6:A6),24)=0,AND(MOD(ROWS(A$6:A6),24 )=17,MOD(ROWS(A$6:A6),24)<=23))

Click the Format button
Select a BLUE fill color
OK out

--
Biff
Microsoft Excel MVP


"Sheeloo" <="to" & CHAR(95) & "sheeloo" & CHAR(64) & "hotmail.com" wrote in
message ...
Essentially you need to get the same no. (SAY IN COL D) 1 for the first 8
nos, then 2 for next 8, and finally 3 for next 8 and then repeat the
pattern.
Then format conditionally like (after selecting the whole range)
Condition 1 FORMULA IS =$D1=1 WHITE
Condition 2 FORMULA IS =$D1=2 GREY
Condition 1 FORMULA IS =$D1=3 BLUE

I have done it in the following way, you can combine the formulae to get
into one Col.

Enter in A6
=MOD(ROW()+2,24)

Enter in B6
=MOD(A6,8)

Enter in C6
1
and in C7
=IF(B7=0,C6+1,C6)


Enter in D6
=MOD(C6-1,3)+1

and copy the formulae down (careful for C as you have to copy down from
C7)

--
Always provide your feedback...


"Cathy" wrote:

I have a large spreadsheet that I'd like to use conditional formatting on
the
rows. I've seen examples on how to apply it to every other row, but in
my
case, I have groups of data that remains together in blocks of 8 rows
each
(this is consistent). The other issue, is that I want the formatting to
start on row 6 (the consistent blocking starts on row 7). I often need
to
insert another "block" into the spreadsheet and find myself re-formatting
the
cell shading all throughout the spreadsheet.

Any ideas on how I could use conditional formatting to make the first
block
of 8 rows white, next 8 grey, next 8 blue and then repeat the conditional
formatting?





row 1 headers
rows 2 & 3 blank
row 4 (headers) Month, Footage
row 5 (headers) Customer Building, HDD, Customer TYPE
rows 6-13 8 data rows (want them white)
rows 14-21 8 data rows (want them grey)
rows 22-29 8 data rows (want them blue)
repeat this conditional formatting on the color

--
Cathy