Our line will be dynamic and will react to any data changes automatically. Naturally, we are not going to 'tie' a line to the x-axis because we don't want to reposition it every time the source data changes. To highlight an important data point in a scatter chart and clearly define its position on the x-axis (or both x and y axes), you can create a vertical line for that specific data point like shown below: Insert vertical line in Excel bar chart.
We will just have to do a little lateral thinking! However, 'no easy way' does not mean no way at all. But there is still no easy way to draw a vertical line in Excel graph. In the modern versions of Excel 2013, Excel 2016 and Excel 2019, you can add a horizontal line to a chart with a few clicks, whether it's an average line, target line, benchmark, baseline or whatever. You will also learn how to make a vertical line interactive with a scroll bar. The tutorial shows how to insert vertical line in Excel chart including a scatter plot, bar chart and line graph.
