Inventory spreadsheet

I have an inventory spreadsheet that I update everyday. What I want to do is to be able to report how much inventory was used in a week. There are no dates associated with the entries I make. I am still pondering as to how to accomplish this without entering data more than once. Any ideas would be very much appreciated.

How are you expecting a Macro to sort and distinguish your entries, and which were for which week, with no dates?

I understand that poses a problem. I had originally thought of having a second tab where I would make my daily entries. Then at the end of the week, update the base inventory but I could use the second tab to make my report. The obstacle I'm encountering is how do I have the update to the original inventory be permanent when I start a new week and have to zero out the data on the second tab? I had figured on writing a formula that would add the weekly inventory to the base inventory but I don't think that will work. Would there be a way to just add my daily inventory to the base spreadsheet and have it populate a duplicate spreadsheet at the same time? That way after one week I could just report off the duplicate spreadsheet and could zero it out without affecting the base inventory.

why not just add a column with the current date stamp when entered.?

How would you then collect the data for just one week?

would it work to input a "from" and "to" date and pull from that?

I suppose that might work, just not clear on how to implement that.