A bar chart provides a way of showing data values represented as vertical bars. It is sometimes used to show trend data, and the comparison of multiple data sets side by side.
| `barPercentage` | `number` | `0.9` | Percent (0-1) of the available width each bar should be within the category width. 1.0 will take the whole category width and put the bars right next to each other. [more...](#barpercentage-vs-categorypercentage)
| `categoryPercentage` | `number` | `0.8` | Percent (0-1) of the available width each category should be within the sample width. [more...](#barpercentage-vs-categorypercentage)
| `barThickness` | <code>number|string</code> | | Manually set width of each bar in pixels. If set to `'flex'`, it computes "optimal" sample widths that globally arrange bars side by side. If not set (default), bars are equally sized based on the smallest interval. [more...](#barthickness)
| `maxBarThickness` | `number` | | Set this to ensure that bars are not sized thicker than this.
| `minBarLength` | `number` | | Set this to ensure that bars have a minimum length in pixels.
| `gridLines.offsetGridLines` | `boolean` | `true` | If true, the bars for a particular data point fall between the grid lines. The grid line will move to the left by one half of the tick interval. If false, the grid line will go right down the middle of the bars. [more...](#offsetgridlines)
If this value is a number, it is applied to the width of each bar, in pixels. When this is enforced, `barPercentage` and `categoryPercentage` are ignored.
If set to `'flex'`, the base sample widths are calculated automatically based on the previous and following samples so that they take the full available widths without overlap. Then, bars are sized using `barPercentage` and `categoryPercentage`. There is no gap when the percentage options are 1. This mode generates bars with different widths when data are not evenly spaced.
If not set (default), the base sample widths are calculated using the smallest interval that prevents bar overlapping, and bars are sized using `barPercentage` and `categoryPercentage`. This mode always generates bars equally sized.
### offsetGridLines
If true, the bars for a particular data point fall between the grid lines. The grid line will move to the left by one half of the tick interval, which is the space between the grid lines. If false, the grid line will go right down the middle of the bars. This is set to true for a category scale in a bar chart while false for other scales or chart types by default.
It is common to want to apply a configuration setting to all created bar charts. The global bar chart settings are stored in `Chart.defaults.bar`. Changing the global options only affects charts created after the change. Existing charts are not changed.
## barPercentage vs categoryPercentage
The following shows the relationship between the bar percentage option and the category percentage option.
The `data` property of a dataset for a bar chart is specified as an array of numbers. Each point in the data array corresponds to the label at the same index on the x axis.
Bar charts can be configured into stacked bar charts by changing the settings on the X and Y axes to enable stacking. Stacked bar charts can be used to show how one data series is made up of a number of smaller pieces.
```javascript
var stackedBar = new Chart(ctx, {
type: 'bar',
data: data,
options: {
scales: {
xAxes: [{
stacked: true
}],
yAxes: [{
stacked: true
}]
}
}
});
```
## Dataset Properties
The following dataset properties are specific to stacked bar charts.
A horizontal bar chart is a variation on a vertical bar chart. It is sometimes used to show trend data, and the comparison of multiple data sets side by side.
The configuration options for the horizontal bar chart are the same as for the [bar chart](#scale-configuration). However, any options specified on the x axis in a bar chart, are applied to the y axis in a horizontal bar chart.