Add reference lines to charts

Highlight values of interest in your charts and visualize progress towards your goals.

You can add horizontal or vertical lines to a chart that show how the data compares to a reference value. For example, you can use reference lines to visualize daily sales against a target sales figure, or show the average revenue per store and compare each store to that average.

Reference line example: weekly sales vs. target.

Reference line example: weekly sales vs. target.

Reference lines vs. trend lines

Reference lines let you show target values and set thresholds and benchmarks so you can see how your data matches expectations or goals.

Trend lines reveal the overall direction of the data in a chart. Trend lines can help you see patterns and make predictions from otherwise random-appearing data. In Data Studio, you can add trend lines to time series and scatter charts.

Add a reference line

  1. Edit your report.
  2. Select a supported chart.
  3. On the right, open the STYLE properties panel.
  4. Click Add a reference line.
  5. Configure the reference line using the options below.

You can add up to 10 reference lines per chart.

View a reference line

Reference lines appear with either a default label, or a custom label you supply. Hover over the line to display a tooltip showing the reference value.

Supported charts

You can add reference lines to time series, line and combo charts, bar and column charts, area charts, and scatter charts. Not all options are available for all charts. See the limits section below.

Reference line options


You can base a reference line on a constant value or a calculated value.

Constant value - select this option, then enter a number in the Value field. For example, if your sales target is $10,000 per day, enter 10000. For a percentage value, enter the number as a decimal (.5 equals 50%).

Calculated value - select this option, then select a metric in the chart, then select a calculation to apply.


Choose an aggregation to apply to the selected metric. For example, if the chart is visualizing Users by Week, you can create a reference line showing the average number of weekly users by choosing the Users metric and Average calculation.

Available calculations:

  • Average
  • Median
  • Percentile
    • Enter the percentile as a whole number between 0 and 100.
  • Min
  • Max

You can only create calculated reference lines based on metrics that appear in the chart.


Display the reference line on the chart's X, Y, Left-Y, or Right-Y axis. This option only applies to constant value reference lines. The available axes depend on the chart type.


Display a custom label for the reference line.

If you leave this blank, Data Studio supplies a default label. For constant value reference lines, the label is "Reference Line #n." For calculated reference lines, the default label is the type of calculation applied.

Line color, weight and style

Set the appearance of the reference line.

Remove a reference line

To remove a reference line from a chart:

  1. Edit your report.
  2. Select the chart.
  3. On the right, open the STYLE properties panel.
  4. Locate the reference line you want to remove, then click Remove icon..

Edit charts with reference lines

If you change the chart type, Data Studio deletes any reference lines not supported by the new chart type.

If you remove a metric from the chart, Data Studio deletes any calculated-value reference lines associated with that metric.

Limits of reference lines

  • Reference lines are only available for numeric axes. Reference lines on date axes aren't supported.
  • Calculated reference lines only include values currently displayed in the chart. For example, if you add a reference line to a bar chart with 10 bars, data from any additional bars aren't included in the calculation.
  • You can't add a reference line to 100% stacked charts.
  • Stacked column, stacked bar, and stacked area charts only support constant value reference lines.
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