because excel stores data as integer you can subtract them:
formula is =B1-A17
and then you set the background to red or whatever you want.
Then you can copy this format down.

hth

Carlo

On Nov 22, 10:43 am, Jason Au Yeung
wrote:
Hi, I would like to use the conditional formatting. I can use it for numeric,
but how to count date for 2 column ?

If I want column B can not be 7 days more than column A. If not, Column B
will show a different colour. How can it be done ?

Hardware deliver date Deployment Date
1 1/11/2007 2/11/2007
2 1/11/2007 1/19/2007
3 12/11/2007 12/15/2007
4 12/12/2007 12/15/2007
5 12/13/2007 12/20/2007
6 12/14/2007 12/20/2007
7 12/15/2007 12/20/2007

Suppose 2 b & 5 b will show a different colour. Many thanks