# Forecast band

> Where it is heading, and how sure we are. Sample data: cash on hand, May to April, actual to October, P10–P90 band.

- Type 015 · Change over time
- Component: `<ForecastBand>`, the same name as the Figma component
- Install: `npx shadcn add @chartory/forecast-band` (free in Hearth: the public registry, no token; Signal with Code and Complete)
- Type page: https://usechartory.com/charts/forecast-band

## Installation

1. **Set up the registry once.** This chart is free in Hearth and MIT licensed: no token. Add @chartory to components.json once (the URL alone, no headers), or skip this when another chart is already installed. [Installation guide](https://usechartory.com/docs/installation)

2. **Add the chart.** One command adds the Forecast band component to your project.

```bash
npx shadcn add @chartory/forecast-band
```

3. **Use it.** Pass your rows. The props are the Figma properties.

usage.tsx:

```tsx
import { ForecastBand }
  from "@/components/chartory/forecast-band"

<ForecastBand
  data={cashForecast}
  size="m"
  legend
/>
```

## Props

### `<ForecastBand>`

Every prop but data is a Figma property with the same name and values.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| data | ForecastBandData | Required | The chart's data. The tables below list every field. |
| size | "xs" \| "s" \| "m" \| "l" | "m" | The size class. Each one is laid out again from the data. |
| legend | boolean | true | Shows the legend row under the plot. |
| color | "cat-1" \| "cat-2" \| "cat-3" \| "cat-4" | "cat-1" | The data colour of the primary marks (data/primary). |

### ForecastBandData

The data prop: one object for the whole chart.

| Prop | Type | Default | Note |
| --- | --- | --- | --- |
| mid | number[] | Required | The middle values. |
| hi | number[] | Required | The upper values. |
| lo | number[] | Required | The lower values. |
| split | number | Required | Where the actuals end and the forecast starts (index). |
| min | number | Required | The bottom of the value scale. |
| max | number | Required | The top of the value scale. |
| ticks | string[] | Required | The axis tick labels. |
| xl | Record<number, string> | Required | The x axis labels, by index. |

## Forecast band chart: a React and Figma chart in four sizes

### What does a forecast band chart show?

A forecast band chart shows the actual line up to today and a forecast after it, with a shaded band for the range of likely outcomes. The band widens with time as certainty drops. Use it for cash, demand and capacity plans.

Chartory ships it as a Figma component and a React component with the same name. The code installs from the shadcn registry with one command and lands in your project as a file you own.

### What is the Forecast band component?

It is one **<ForecastBand>** component. Its props are the Figma properties with the same names and values, and the props table above lists them. The data is actuals, then a forecast with a low and a high.

Sizes **XS**, **S**, **M** and **L** re-lay the chart out from the data instead of scaling it, so labels stay readable at every size.

### When should I use it?

- **Is there a range around the forecast?** Yes means the forecast band fits.
- **Is it open-ended, with no budget to burn?** Yes means the forecast band fits.
- **Does it continue a trend?** Yes means the forecast band fits.

### When does another type fit better?

- **A single forecast line.** Use Line chart instead.
- **A budget to burn against.** Use Budget runway instead.
- **Steps between two totals.** Use Waterfall instead.

## Forecast band questions

### Does the Forecast band chart work with shadcn/ui?

Yes. It installs through the shadcn registry with the shadcn CLI, and the file lands in your project.

### How do I install it?

It is free in Hearth and MIT licensed: add the @chartory registry URL once, no token, then run npx shadcn add @chartory/forecast-band. The Installation guide has the steps.

### Can my coding agent install it?

Yes. Connect the Chartory MCP server and ask for the forecast band chart; the agent runs the same command and you review the diff.

### What data does it expect?

Actuals, then a forecast with a low and a high. The sample data comes with the component, and the props table lists every field.

### Which sizes does it ship in?

XS, S, M and L, in Figma and in code. Each size is laid out again from the data, so text and lines keep their size.

### Is it in the Figma file too?

Yes. chart/015-forecast-band has the same properties as the component.

### Does it follow light and dark mode?

Yes. Every paint is a token, so the chart follows light and dark mode and the collection you pick.

### Which plan has the code?

None for Hearth: it is free in the public registry, no token. The Signal collection (@chartory/signal) comes with Code and Complete.