Hi, I have a file that I use to chart some data. I update the data every week with new data from the previous week. I have the date, (ie each day) in the first colum and the next few colums contain the data for that day. When I update the data, I have to go to each chart and update the source data so that the chart will show the new data. I would like to automate this process using a little macro. One idea I had was to update a cell each time the data is added, with the row number that the data list extends to. The macro could use this to create a new source data address so that the chart could be updated. So the question is how do I create this: ActiveChart.SeriesCollection(1).Values = "='Historical Data'!R7C5:R140C5" using a macro. Thanks John.