Summary  
This chapter covers creating combo charts by combining different chart types for each data series and using a secondary axis to handle differing value scales.

General domain of usage  
Data visualization

Combo charts combine two chart types in one visualization. They are used when two data series have different scales but need to be shown together.
A common example is: revenue (large numbers) and conversion rate (percentage).

If both are plotted on the same axis, one series becomes unreadable. A secondary axis solves this.

## Creating a Combo Chart
1. Select the dataset with multiple numeric series;
2. Go to **Insert**;
3. Choose **Combo Chart**;
4. Assign different chart types to each data series;
5. Enable **Secondary Axis** for the series with a different scale.

Excel will display one axis on the left and another on the right.

Data series have significantly different value ranges.

One series becomes compressed or unreadable.

You need to compare trends, not absolute values.

Using the provided dataset:
- Insert a Combo Chart;
- Set one series as a Column Chart;
- Set the second series as a Line Chart;
- Enable a Secondary Axis for the line series.

Goal: display both series clearly despite different value scales.

Master column, line, pie, scatter, combo, and waterfall charts to communicate data clearly in Excel. Apply trendlines, secondary axes, Excel Tables, slicers, dynamic formula-driven ranges, and sparklines to build interactive visual reports.

Build mechanical skill and confidence with Excel's essential chart types.

Apply advanced Excel charting techniques to create professional, insightful visualizations.

Move from static reporting to interactive, decision-support tools in Excel.

Use a secondary axis when:	Avoid using secondary axes when:
Data series have significantly different value ranges.	Scales are similar.
One series becomes compressed or unreadable.	It creates confusion.
You need to compare trends, not absolute values.	The relationship becomes misleading.

Combo Charts and Secondary Axes

Creating a Combo Chart

When to Use a Secondary Axis