Hey, this is my first post so I'll try to be as detailed and succinct as possible. I have an excel worksheet with around 2450 entries. Each entry (row) has information about a specific hotel booking at the same hotel. The hotel in question has 7 rooms. The columns of the worksheet have the date the reservation was made, the arrival date, the checkout date, the number of nights stayed, and the number of rooms reserved. What I need is to create another column which tells me how many rooms were available at the time that the booking was made.

Any thoughts?
Thanks so much for your help.