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# Add a Horizontal Line to a Column or Line Chart: Series Method.

How do you add a nice horizontal line to a column or line chart, to show a target value, or the series average? The method involves adding a new series, applying it to the secondary axes, and making the secondary axes disappear.

Use this data to make a column or line chart. The blank cell in the upper left of this range tells Excel that "Value" is the series names, and the dates in the first column are the category (X axis) labels. (I use dates in this example, but you could use any type of category labels.)

```[blank]    Value
11/11/02     15
11/10/02     16
11/9/02     16
11/8/02     10
11/7/02     14
11/6/02      9
11/5/02     10
11/4/02      8
11/3/02      6
11/2/02      4
11/1/02      3
10/31/02      3
```

In a free section of your worksheet, set up a range with X and Y values corresponding to the endpoints of your indicator line, shown below. The X value ranges from 0 to 1; we will use the secondary X axis for this line, and scale its min and max to 0 and 1. The Y value corresponds to an average or other significant level you want to indicate on the chart.

```[blank]    Average
0         9.5
1         9.5
```

Select and copy this range, select the chart, and from the Edit menu, choose Paste Special. Select the New Series, Categories in First Column, and Series Names in First Row options. The new series has the same style (Column or Line) as the first series.

Right click on the new series "Average" and select Chart Type from the pop up menu. Choose the XY Scatter type, subtype Scatter with data points connected by lines without markers. The series changes and secondary axes appear on the chart.

Now it's time to neaten up the axes. Double click on the secondary X axis, and on the Scale tab, set 0 for Minimum and 1 for Maximum. On the Patterns tab, choose None for Major and Minor Tick Marks and for Tick Mark labels to make the axis disappear.

Select the secondary Y axis and press Delete (or more formally: right click on the chart, choose Chart Options from the Pop Up menu, click on the Axes tab, and uncheck the box for the Secondary Y Axis).

All that may be left is some embellishing of the chart. I removed the legend, added data labels (Show Values option) to the original series, and a data label to the last point of the horizontal line series (see Label Last Point). Then I colored the label text to match the series color.

VertizontalLine.zip is a zipped workbook that shows this technique and others for reliably placing a vertical or horizontal line on your column or line chart, using a dummy series or a dummy error bar. Here are some related pages on this site:

Add a Vertical Line to a Column or Line Chart: Series Method.

Add a Horizontal Line to a Column or Line Chart: Error Bar Method.

Add a Vertical Line to a Column or Line Chart: Error Bar Method.