> AI agents: this is one page from Mammoth Analytics documentation. The index of all pages as Markdown is https://mammoth.io/docs/llms.txt. Append `.md` to any docs URL, or send `Accept: text/markdown`, to get Markdown.

# Add a target line, event marker or caption to a chart

> Pin a target line or event marker on a Mammoth dashboard chart, and add a caveat or source caption with values that stay current.
>
> Applies to: Roles: Anyone who can edit the dashboard. Where: Dashboard editor › click a chart › Annotations

A chart's edit panel can pin a labelled line at a value, a marker on one point of the x-axis, and a caption under the chart. Click a chart in the dashboard editor to open its edit panel; anyone who can edit the dashboard can add them. For colours, formats and axes, see [Style a dashboard chart](https://mammoth.io/docs/learn/dashboards/chart-options/).

## Add a target line or event marker to a chart

The **Annotations** section pins a labelled line at a value (a target or an average), or a labelled marker on one point of the x-axis (a launch, a price change). It's on **Bar**, **Bar (H)**, **Line**, **Area**, **Grouped bar**, **Combo**, **Stacked bar** and **Stacked area** charts.

| Button | Adds | Fields |
|---|---|---|
| **+ Reference line** | A **Reference** row: a horizontal line | **Value** (a number) and **Label** |
| **+ Event** | An **Event** row: a marker on one x-axis point | A point (**Pick a date**) and a **Label** |

- The event's point list holds the labels on the chart's own x-axis, so an event can only sit on a point the chart shows. **+ Event** is disabled when the chart has no x-axis labels.
- Every row has a **Color**: **Default**, **Brand**, **Positive**, **Negative**, **Warning** or **Info**. The colours follow the dashboard theme.
- **×** removes a row.
- On a chart with more than one axis, each row also asks "Which axis this value belongs to".

The line and label redraw as you type.

Example: to mark a sales target of 50,000:

1. Click **+ Reference line**.
2. Set **Value** to 50000.
3. Set **Label** to "Target".
4. Set **Color** to **Positive**.



## Add a caveat or source caption under a chart

A caption is one or two lines of text under a single chart. It says what the chart leaves out or where its numbers come from.

1. Near the bottom of the panel, tick **Add a caption**.
2. Pick the kind: **Caveat** ("A limit on what the numbers cover", the default) or **Source** ("Where the data came from").
3. Type the text (placeholder "Excludes Head Office…").

**Bold**, **Italic** and **Link** buttons format it: "One or two lines, under the chart. **bold**, _italic_ and [links](url) are supported."

## Insert values that stay current in a caption

The **{ }** button ("Insert something the board fills in") adds a value the dashboard keeps current. It appears when the dashboard has these facts:

| Value | What it shows |
|---|---|
| `{updated}` | When this board was last built |
| `{rows}` | How many rows it covers |
| `{range}` | The period the data covers |
| `{dataset}` | The dataset this board reads |
| `{filters}` | What the reader has filtered to |

Untick **Add a caption** to delete the caption. For notes about the whole dashboard rather than one chart, use a [text block](https://mammoth.io/docs/learn/dashboards/text-blocks/#add-a-note-caveat-or-source-text-block).

## Related

- [Style a dashboard chart](https://mammoth.io/docs/learn/dashboards/chart-options/): the **Reference line** option and other styles.
- [Several measures or two axes](https://mammoth.io/docs/learn/dashboards/chart-measures/): which axis a line belongs to.
- [Add a note, caveat or source text block](https://mammoth.io/docs/learn/dashboards/text-blocks/): notes for the whole board.

---
Source: https://mammoth.io/docs/learn/dashboards/chart-annotations.md · Updated: 2026-11-08