This tip explains how to make a dual-axis chart in Excel 2007- absolutely vital if you want to show two different metrics on one graph.
Displaying two sets of data on one chart is simple when you know how. First, select your data as normal and make a standard side-by-side column chart. Next right click on the second series of data within the graph – click on ‘Change Series Chart Type’…
Select a standard line graph, then right click on the line and this time select Format Data Series…(N.B. if you don’t want your second data series to be a line then it’s more complicated – another tip, another time)
Click the option for Secondary Axis and hit Close
Now your graph shows two separate metrics on different axes. Just remember to label the axes now so that the graph is easy to read.