Sum data based on criteria

Hello all,
I am trying to get a sum of the products from multiple cells, without having to constantly change the formula. Example attached.
[ATTACH]347001[/ATTACH

Each date, a new number is entered. I would like to be able to apply a blanket formula to multiply the respective "case weight" times the number of cases run. If multiple rows are used, a different case weight applies. The sum of each days total weight will show below.

I had originally used '=D4*$B4/1000, then having to change the formula each day for each different item.

Any help would be appreciated.

Mod note: thread title changed

Hi, welcome to the forum

I think what you are looking for is the SUMIF() function.

Please upload a sample workbook of your data, not a pic, we cant work with pics