=MAX(0,MIN(KeyDateEnd,$B1+1)-MAX(KeyDateStart,$A1))+1

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__________________________________
HTH

Bob

"liztownsend" wrote in message
...
Hope someone can help, I'm looking for a formula to work out date
overlaps.
e.g.
If my key dates are 1/11/08 to 30/11/08
I want to auto calculate how many days the following overlap with my key
dates
01/01/08 to 31/12/08
16/11/08 to 05/12/08
etc

thanks!
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Liz