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---
title: Line Chart
---
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A line chart is a way of plotting data points on a line. Often, it is used to show trend data, or the comparison of two data sets.
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import { useEffect } from 'react';
export const ExampleChart = () => {
useEffect(() => {
const cfg = {
type: 'line',
data: {
labels: [
'January',
'February',
'March',
'April',
'May',
'June',
'July'
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],
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datasets: [{
label: 'My First Dataset',
data: [65, 59, 80, 81, 56, 55, 40],
fill: false,
borderColor: 'rgb(75, 192, 192)',
lineTension: 0.1
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}]
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},
options: {
}
};
new Chart(document.getElementById('chartjs-0').getContext('2d'), cfg);
});
return <div className="chartjs-wrapper"><canvas id="chartjs-0" className="chartjs"></canvas></div>;
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}
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<ExampleChart/>
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## Example Usage
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```javascript
var myLineChart = new Chart(ctx, {
type: 'line',
data: data,
options: options
});
```
## Dataset Properties
The line chart allows a number of properties to be specified for each dataset. These are used to set display properties for a specific dataset. For example, the colour of a line is generally set this way.
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| Name | Type | [Scriptable](../general/options.md#scriptable-options) | [Indexable](../general/options.md#indexable-options) | Default
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| ---- | ---- | :----: | :----: | ----
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| [`backgroundColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `'rgba(0, 0, 0, 0.1)'`
| [`borderCapStyle`](#line-styling) | `string` | Yes | - | `'butt'`
| [`borderColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `'rgba(0, 0, 0, 0.1)'`
| [`borderDash`](#line-styling) | `number[]` | Yes | - | `[]`
| [`borderDashOffset`](#line-styling) | `number` | Yes | - | `0.0`
| [`borderJoinStyle`](#line-styling) | `string` | Yes | - | `'miter'`
| [`borderWidth`](#line-styling) | `number` | Yes | - | `3`
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| [`clip`](#general) | `number`\|`object` | - | - | `undefined`
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| [`cubicInterpolationMode`](#cubicinterpolationmode) | `string` | Yes | - | `'default'`
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| [`fill`](#line-styling) | `boolean`\|`string` | Yes | - | `true`
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| [`hoverBackgroundColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
| [`hoverBorderCapStyle`](#line-styling) | `string` | Yes | - | `undefined`
| [`hoverBorderColor`](#line-styling) | [`Color`](../general/colors.md) | Yes | - | `undefined`
| [`hoverBorderDash`](#line-styling) | `number[]` | Yes | - | `undefined`
| [`hoverBorderDashOffset`](#line-styling) | `number` | Yes | - | `undefined`
| [`hoverBorderJoinStyle`](#line-styling) | `string` | Yes | - | `undefined`
| [`hoverBorderWidth`](#line-styling) | `number` | Yes | - | `undefined`
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| [`label`](#general) | `string` | - | - | `''`
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| [`lineTension`](#line-styling) | `number` | - | - | `0`
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| [`order`](#general) | `number` | - | - | `0`
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| [`pointBackgroundColor`](#point-styling) | `Color` | Yes | Yes | `'rgba(0, 0, 0, 0.1)'`
| [`pointBorderColor`](#point-styling) | `Color` | Yes | Yes | `'rgba(0, 0, 0, 0.1)'`
| [`pointBorderWidth`](#point-styling) | `number` | Yes | Yes | `1`
| [`pointHitRadius`](#point-styling) | `number` | Yes | Yes | `1`
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| [`pointHoverBackgroundColor`](#interactions) | `Color` | Yes | Yes | `undefined`
| [`pointHoverBorderColor`](#interactions) | `Color` | Yes | Yes | `undefined`
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| [`pointHoverBorderWidth`](#interactions) | `number` | Yes | Yes | `1`
| [`pointHoverRadius`](#interactions) | `number` | Yes | Yes | `4`
| [`pointRadius`](#point-styling) | `number` | Yes | Yes | `3`
| [`pointRotation`](#point-styling) | `number` | Yes | Yes | `0`
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| [`pointStyle`](#point-styling) | `string`\|`Image` | Yes | Yes | `'circle'`
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| [`showLine`](#line-styling) | `boolean` | - | - | `undefined`
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| [`spanGaps`](#line-styling) | `boolean`\|`number` | - | - | `undefined`
| [`stepped`](#stepped) | `boolean`\|`string` | - | - | `false`
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| [`xAxisID`](#general) | `string` | - | - | first x axis
| [`yAxisID`](#general) | `string` | - | - | first y axis
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### General
| Name | Description
| ---- | ----
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| `clip` | How to clip relative to chartArea. Positive value allows overflow, negative value clips that many pixels inside chartArea. `0` = clip at chartArea. Clipping can also be configured per side: `clip: {left: 5, top: false, right: -2, bottom: 0}`
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| `label` | The label for the dataset which appears in the legend and tooltips.
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| `order` | The drawing order of dataset. Also affects order for stacking, tooltip, and legend.
| `xAxisID` | The ID of the x-axis to plot this dataset on.
| `yAxisID` | The ID of the y-axis to plot this dataset on.
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### Point Styling
The style of each point can be controlled with the following properties:
| Name | Description
| ---- | ----
| `pointBackgroundColor` | The fill color for points.
| `pointBorderColor` | The border color for points.
| `pointBorderWidth` | The width of the point border in pixels.
| `pointHitRadius` | The pixel size of the non-displayed point that reacts to mouse events.
| `pointRadius` | The radius of the point shape. If set to 0, the point is not rendered.
| `pointRotation` | The rotation of the point in degrees.
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| `pointStyle` | Style of the point. [more...](../configuration/elements.md#point-styles)
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All these values, if `undefined`, fallback first to the dataset options then to the associated [`elements.point.*`](../configuration/elements.md#point-configuration) options.
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### Line Styling
The style of the line can be controlled with the following properties:
| Name | Description
| ---- | ----
| `backgroundColor` | The line fill color.
| `borderCapStyle` | Cap style of the line. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineCap).
| `borderColor` | The line color.
| `borderDash` | Length and spacing of dashes. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/setLineDash).
| `borderDashOffset` | Offset for line dashes. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineDashOffset).
| `borderJoinStyle` | Line joint style. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineJoin).
| `borderWidth` | The line width (in pixels).
| `fill` | How to fill the area under the line. See [area charts](area.md).
| `lineTension` | Bezier curve tension of the line. Set to 0 to draw straightlines. This option is ignored if monotone cubic interpolation is used.
| `showLine` | If false, the line is not drawn for this dataset.
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| `spanGaps` | If true, lines will be drawn between points with no or null data. If false, points with `NaN` data will create a break in the line. Can also be a number specifying the maximum gap length to span. The unit of the value depends on the scale used.
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If the value is `undefined`, `showLine` and `spanGaps` fallback to the associated [chart configuration options](#configuration-options). The rest of the values fallback to the associated [`elements.line.*`](../configuration/elements.md#line-configuration) options.
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### Interactions
The interaction with each point can be controlled with the following properties:
| Name | Description
| ---- | -----------
| `pointHoverBackgroundColor` | Point background color when hovered.
| `pointHoverBorderColor` | Point border color when hovered.
| `pointHoverBorderWidth` | Border width of point when hovered.
| `pointHoverRadius` | The radius of the point when hovered.
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### cubicInterpolationMode
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The following interpolation modes are supported.
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* `'default'`
* `'monotone'`
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The `'default'` algorithm uses a custom weighted cubic interpolation, which produces pleasant curves for all types of datasets.
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The `'monotone'` algorithm is more suited to `y = f(x)` datasets: it preserves monotonicity (or piecewise monotonicity) of the dataset being interpolated, and ensures local extremums (if any) stay at input data points.
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If left untouched (`undefined`), the global `options.elements.line.cubicInterpolationMode` property is used.
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### Stepped
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The following values are supported for `stepped`.
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* `false`: No Step Interpolation (default)
* `true`: Step-before Interpolation (eq. `'before'`)
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* `'before'`: Step-before Interpolation
* `'after'`: Step-after Interpolation
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* `'middle'`: Step-middle Interpolation
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If the `stepped` value is set to anything other than false, `lineTension` will be ignored.
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## Configuration Options
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The line chart defines the following configuration options. These options are merged with the global chart configuration options, `Chart.defaults`, to form the options passed to the chart.
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| Name | Type | Default | Description
| ---- | ---- | ------- | -----------
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| `showLines` | `boolean` | `true` | If false, the lines between points are not drawn.
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| `spanGaps` | `boolean`\|`number` | `false` | If true, lines will be drawn between points with no or null data. If false, points with `NaN` data will create a break in the line. Can also be a number specifying the maximum gap length to span. The unit of the value depends on the scale used.
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## Default Options
It is common to want to apply a configuration setting to all created line charts. The global line chart settings are stored in `Chart.defaults.line`. Changing the global options only affects charts created after the change. Existing charts are not changed.
For example, to configure all line charts with `spanGaps = true` you would do:
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```javascript
Chart.defaults.line.spanGaps = true;
```
## Data Structure
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See [`Data structures`](../general/data-structures.md)
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## Stacked Area Chart
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Line charts can be configured into stacked area charts by changing the settings on the y-axis to enable stacking. Stacked area charts can be used to show how one data trend is made up of a number of smaller pieces.
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```javascript
var stackedLine = new Chart(ctx, {
type: 'line',
data: data,
options: {
scales: {
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y: {
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stacked: true
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}
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}
}
});
```
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## Internal data format
`{x, y}`