I've been reading post after post and I'm just not getting it or it doesnt apply to what I have. Here's the layout. Excel 2007. I have a .CSV I generate from another program that has the date in column A&B(may not need both columns),time incremented every 15 mins in Column C, Flow data from 2 diff flow meters in D & E. Now in another worksheet I'm averaging all flow data for each meter for each day. The problem lies in the program that creates the CSV will only create by number of days, so the CSV will always have a few hours of run over time into the next month. This formula =AVERAGEIF(A:A,A9,E:E) will work for day 1 and =AVERAGEIF(A:A,A9+1,E:E) for day 2 and so on, however I need to make sure it doesnt rollover into the next month. If you have anymore questions or would like to see the actual data im working with just ask. Thanks, Jon.