Combo Chart

Best Practices


The combo chart is a cartesian chart in which multiple data series are represented by a combination of bars, shaded areas, or lines in different styles.  As with a bar or line chart, this chart type is typically used to show significant data changes by category or date, but with the added advantage of highlighting baseline values, target values, etc. In the chart below, end users can quickly see how historical data compare with a monthly goal.

Chart is an interactive content type in the WCMS.  See the examples at the bottom of this page to try out “live” charts.

Screenshot of combo chart with bars and line

A combo chart can also have two value axes, one on the left (the conventional position) and a second axis on the right.  This feature allows you to include data series with different scales in order to show in general how they track with each other.

Chart is an interactive content type in the WCMS.  Go to examples at the bottom of this page to try out “live” charts.


Much of the guidance related to bar and line charts also applies to combo charts. The greatest risk with combo charts is burdening your chart users with too much visual information. Don’t try to do too much in a single chart, as in the example below. And think carefully about how to present the various data series. If your chart users have to repeatedly look at the legend for a reminder of what a particular bar, line, or area style represents, that’s a problem.

Screenshot of combo chart with too many line styles


Chart is an interactive content type. In the examples below, try selecting and deselecting data series in the legends and hovering over the chart.  Also, try sorting the data tables using the headings.

Combo Bar and Area Chart

For each data series, you can select the display style:  Bar, Solid Line, Small Dashed, Medium Dash, Large Dashed, or Area. This example shows bars for four data series with area shading for the fifth. For information on how to set up each data series, see Building in the WCMSSee example data file [XLS – 318 B].

Combo Bar-Line Chart with Stacked Bars

This example shows the stacking of bars in a combo chart.

Note that this example and the epi chart below demonstrate the animation feature.  (Refresh your page to see again.)  This is achieved with the “Animate Visualization” option in the Visual panel.

Epi Curve Style Bar Chart

An epidemic curve, or “epi curve,” is a variation of a standard time-based vertical bar chart.  It typically shows the distribution of outbreak cases along a timeline.

The example below is actually a combo chart showing two data series:  case totals are represented by bars while 7-day averages are represented by a dashed line.

To achieve the results below, the chart designer has used the Bar Thickness option (Visual panel) as well as the options for Number of Ticks and Tick Rotation (Date/Category Axis Panel).  See example data file [XLS – 381 B]

Combo Chart with Two Value Axes

To show a general correlation among data series based on different scales, you can include both a left and a right axis.  The chart below shows such a relationship between Outreach Costs and the number of New Participants. See example data file [XLS – 232 B]

Combo Chart with Suppressed Data

You can suppress data in a line chart for a number of reasons, including privacy concerns or preliminary data. Use the “Add Special Line” section under the Data Series panel.

Please note that for best results, and because users can download the raw data, you will want to use text to suppress the data in your dataset (replaced suppressed values with “SUP” or “ABC” or something similar), rather than just relying on suppressing by numeric value. See example data file [XLS – 443 B].