For example, you have created a column chart in Excel as below screenshot shown. You can add a moving average line in the column chart easily as follows:

Click the column chart to activate the Chart Tools, and then click Design > Add Chart Element > Trendline > Moving Average. See screenshot:

Note: If you are using Excel 2010 or earlier versions, please click the chart to activate the Chart Tools, and then click Layout > Trendline > Two Period Moving Average.

Now the moving average line is added in the column chart immediately. See screenshot:

Note: If you want to change the period of the moving average line, please double click the moving average line in the chart to display the Format Trendline pane, click the Trendline Options icon, and then change the period as you need. See screenshot:

One click to add an average line in an Excel chart

In general, to add an average line in a chart in Excel, we need to figure out the average value and add an average column in the source data range, then add new data series in the chart, and change chart type of the new data series to line. Too complex! Here, you can use the Add Line to Chart feature of Kutools for Excel to add an average line for a chart with only one click!