Add a second Y-axis to a chart
Certain chart types allow you to add a second Y-axis in order to represent your data on two different scales at the same time. This is particularly useful for combo charts, which show two data series. Using the second Y-axis option, you can scale each series separately, making your chart clear and easy to read.
To add a second Y-axis to your chart, go to the Customize tab in the Chart Editor and scroll down to the Data Series section. From the drop-down menu, select the name of the series you’d like to scale to the right. Then, select Right axis from the drop-down menu next to Axis.
You can also add a second Y-axis directly in the chart if you are in quick edit mode, which is accessed by clicking the pencil icon in the top left corner of the chart. For charts that allow a second Y-axis, you can right click on a bar or line in the chart (based on the chart type) and select the right axis icon to add the extra axis.
Example of use
Let’s say that you work in a restaurant and want to chart the amount of fruit consumed and the cost of each type of fruit that your kitchen orders.
Charting this information on a combo chart with a single Y-axis doesn’t work well, because the average cost is a much smaller value than the average number sold. In addition, you are representing two different units (number and dollar value) on your Y-axis, which makes it difficult to label the axis properly.
With the second Y-axis option, however, you can graph the data so that it scales the volume fruit consumed on the left and its cost on the right.