I have two columns.

Column C is labeled: Group
Column D is Labeled: Weight

I have 27 rows with data. I would like to tally the group weights

example: 5 of the 27 rows are under Group number 630 (the cell in column C
has the value 630). Each one has a weight ...I'd like a total weight for all
items with the group number 630 and so forth. I am guessing this is maybe
some kind of lookup function but have no idea on how to add each room with
the same group number.

Thanks in Advance