Assuming if someone is off on a Friday and a Monday, you want that to count
as 2 consecutive days.

Try this:
=IF(WORKDAY(B2,-1)=B1,C1+1,1)

(If the WORKDAY function is not available, and returns the #NAME? error,
install and load the Analysis ToolPak add-in.)

Otherwise:
=IF(B2-B11,1,C1+1)

Does that help?

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Regards,
Ron