> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://help.sigmacomputing.com/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://help.sigmacomputing.com/_mcp/server. # Display chart reference marks > Display chart reference marks in Sigma to highlight averages, medians, min/max values, custom metrics, or formulas as lines or bands. Reference marks visually highlight important information about charts, including averages, medians, minimum and maximum values, custom values, and formulas. You can configure them to appear as either lines or bands. Reference lines and reference bands are available for the following visualization types: * [Bar charts](/docs/build-a-bar-chart) * [Line charts](/docs/build-a-line-chart) * [Area charts](/docs/area-charts) * [Scatter charts](/docs/build-a-scatter-plot) * [Combo charts](/docs/combo-charts) * [KPI charts](/docs/build-a-kpi-chart) * [Waterfall charts](/docs/build-a-waterfall-chart) ## User requirements * To customize a chart in a workbook, you must be assigned an [account type](/docs/account-type-and-license-overview) with **Full explore** or **Create, edit, and publish workbooks** permission enabled. * To customize a chart in a report, you must be assigned an [account type](/docs/account-type-and-license-overview) with the **Create, edit, and publish reports** permission enabled. * You must be the document owner or be granted **Can explore** or **Can edit** [access to the document](/docs/folder-and-document-permissions). ## Add a reference line A reference line marks a single value on a chart, such as a target, threshold, or average. To plot a reference line, do the following: 1. Open a workbook or report for customizing or editing. 2. Select the chart you want to modify. 3. In the editor panel, select **Format**, then click **Reference marks** to expand the section. 4. Click **+ Add new**. 5. For **Line or band**, select **Line**. 6. For **Axis**, select the axis you want to plot the line on. 7. For **Value**, configure the location of the reference line: * To use a fixed value, select **Constant** and enter the value you want to use. * To calculate the value from your data, select an aggregate, such as **Min**, **Max**, **Sum**, or **Avg**, then select a column to aggregate. ![The Reference marks panel with Line selected and an Avg Sum of Sales reference line drawn across a bar chart titled Sum of Sales by Month of Date.](https://fdr-prod-docs-files-public.s3.us-east-1.amazonaws.com/sigma.docs.buildwithfern.com/52720d291a9948c9c12d0bb076ee64a16691c040b69117664361326e3ff10e65/assets/docs-images/c5fd440a6a784dba38bd0840b238f0e9467eb957341705ac8de759a66ebb683b-referencemarkers.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6KXJSKKNFOCF7G4B%2F20260727%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20260727T054244Z&X-Amz-Expires=604800&X-Amz-Signature=03b75320cdfad3f30668a9be9f0e63ee9d8b0004a3b9d4f336c2755f72ead5e8&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject) 8. (Optional) To customize the appearance of the line, configure any of the following optional settings: | Setting | Description | | :------------- | :------------------------------------------------------------------------------------------------------------------------------------ | | **Line style** | The pattern (**Solid**, **Dashed**, or **Dotted**), width, and color of the line. | | **Show label** | Display a label for the reference line on the chart. | | **Show value** | Display the line's value on the chart. You can also choose where on the chart the value displays, as well as the text color and size. | ## Add a reference band A reference band highlights a range between two values, such as an acceptable range or a confidence interval. To plot a reference band, do the following: 1. Open a workbook or report for customizing or editing. 2. Select the chart you want to modify. 3. In the editor panel, select **Format**, then click **Reference marks** to expand the section. 4. Click **+ Add new**. 5. For **Line or band**, select **Band**. 6. For **Axis**, select the axis you want to plot the band on. 7. For **Band start**, configure the value where the band begins: * To use a fixed value, select **Constant** and enter the value you want to use. * To calculate the value from your data, select an aggregate, such as **Min**, **Max**, **Sum**, or **Avg**, then select a column to aggregate. 8. For **Band end**, configure the value where the band ends, using the same options as **Band start**. 9. (Optional) To customize the appearance of the band, configure any of the following optional settings: | Setting | Description | | :------------------- | :------------------------------------------------------------------------------------------------------------------------------------ | | **Background color** | The fill color of the band. | | **Show line** | Display a line for the band start and band end. You can also choose the style, width, and color of the lines. | | **Show label** | Display a label for the reference band on the chart. | | **Show value** | Display the band's value on the chart. You can also choose where on the chart the value displays, as well as the text color and size. | ## Duplicate a reference mark To create a copy of an existing reference mark and its settings: 1. In the **Reference marks** section of the **Format** tab, click the reference mark you want to duplicate. 2. Select **Duplicate**. The popover for the duplicated reference mark opens. ## Related resources * [Intro to charts](/docs/intro-to-visualizations)