In this tutorial, you will learn how to add a horizontal line to a chart in Google Sheet.
How to Add a Horizontal Line to a Chart in Google Sheets
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Horizontal lines are commonly used to analyze a data group or highlight connections between data. You might want to add a horizontal line to a Google Sheets chart to indicate a target line, an average line, or another measure on occasion.
Once you are ready, we can get started by using real-life scenarios to help you understand how to plot multiple lines in Google Sheets.
Add a Horizontal Line to a Chart
Assuming we already have a column chart on our Google Sheet, we will now learn how to add a horizontal line to the existing column chart.
Step 1
Double click on the column chart to access the Chart Editor. The Chart Editor will appear on the right side of your screen.

Step 2
To add the horizontal line, we will need to change the chart type to a combo line chart. Select Chart Type, and select Combo Chart in the Line Chart section.

Step 3
Next, we can customize the line to our preference. For this example, we will go to Series and change the Line Dash Type to Dotted to signify the lowest threshold for the inventories.

Step 4
Once you are done editing and customizing the horizontal line, it will look something like this.

Summary
That’s all there is to it. You are welcome to copy the example spreadsheet below to see how it is done. The most crucial lesson is to enjoy yourself while doing it.
Example Spreadsheet: Make a copy of the example spreadsheet
In this tutorial, I covered how to make categories in google sheets. Want more? Check out all the Google Sheets Tutorials.