---
layout: docs
title: Containers
description: Containers are a fundamental building block of Bootstrap that contain, pad, and align your content withing a given device or viewport.
group: layout
toc: true
---

## How they work

Containers are the most basic layout element in Bootstrap and are **required when using our default grid system**. Containers are used to contain, pad, and (sometimes) center the content within them. While containers *can* be nested, most layouts do not require a nested container.

Bootstrap comes with three different containers:

- `.container`, which sets a `max-width` at each responsive breakpoint
- `.container-fluid`, which is `width: 100%` at all breakpoints
- `.container-{breakpoint}`, which is `width: 100%` until the specified breakpoint

The table below illustrates how each container's `max-width` compares to the original `.container` and `.container-fluid` across each breakpoint.

See them in action and compare them in our [Grid example]({{< docsref "/examples/grid#containers" >}}).

<table class="table text-left">
  <thead>
    <tr>
      <th></th>
      <th>
        Extra small<br>
        <span class="font-weight-normal">&lt;576px</span>
      </th>
      <th>
        Small<br>
        <span class="font-weight-normal">&ge;576px</span>
      </th>
      <th>
        Medium<br>
        <span class="font-weight-normal">&ge;768px</span>
      </th>
      <th>
        Large<br>
        <span class="font-weight-normal">&ge;992px</span>
      </th>
      <th>
        X-Large<br>
        <span class="font-weight-normal">&ge;1200px</span>
      </th>
      <th>
        XX-Large<br>
        <span class="font-weight-normal">&ge;1400px</span>
      </th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td><code>.container</code></td>
      <td class="text-muted">100%</td>
      <td>540px</td>
      <td>720px</td>
      <td>960px</td>
      <td>1140px</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-sm</code></td>
      <td class="text-muted">100%</td>
      <td>540px</td>
      <td>720px</td>
      <td>960px</td>
      <td>1140px</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-md</code></td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td>720px</td>
      <td>960px</td>
      <td>1140px</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-lg</code></td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td>960px</td>
      <td>1140px</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-xl</code></td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td>1140px</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-xxl</code></td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td>1320px</td>
    </tr>
    <tr>
      <td><code>.container-fluid</code></td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
      <td class="text-muted">100%</td>
    </tr>
  </tbody>
</table>

## Default container

Our default `.container` class is a responsive, fixed-width container, meaning its `max-width` changes at each breakpoint.

{{< highlight html >}}
<div class="container">
  <!-- Content here -->
</div>
{{< /highlight >}}

## Responsive containers

Responsive containers allow you to specify a class that is 100% wide until the specified breakpoint is reached, after which we apply `max-width`s for each of the higher breakpoints. For example, `.container-sm` is 100% wide to start until the `sm` breakpoint is reached, where it will scale up with `md`, `lg`, `xl`, and `xxl`.

{{< highlight html >}}
<div class="container-sm">100% wide until small breakpoint</div>
<div class="container-md">100% wide until medium breakpoint</div>
<div class="container-lg">100% wide until large breakpoint</div>
<div class="container-xl">100% wide until extra large breakpoint</div>
<div class="container-xxl">100% wide until extra extra large breakpoint</div>
{{< /highlight >}}

## Fluid containers

Use `.container-fluid` for a full width container, spanning the entire width of the viewport.

{{< highlight html >}}
<div class="container-fluid">
  ...
</div>
{{< /highlight >}}

## Sass

As shown above, Bootstrap generates a series of predefined container classes to help you build the layouts you desire. You may customize these predefined container classes by modifying the Sass map (found in `_variables.scss`) that powers them:

{{< highlight scss >}}
$container-max-widths: (
  sm: 540px,
  md: 720px,
  lg: 960px,
  xl: 1140px,
  xxl: 1320px
) !default;
{{< /highlight >}}

In addition to customizing the Sass, you can also create your own containers with our Sass mixin.

{{< highlight scss >}}
// Source mixin
@mixin make-container($padding-x: $container-padding-x) {
  width: 100%;
  padding-right: $padding-x;
  padding-left: $padding-x;
  margin-right: auto;
  margin-left: auto;
}

// Usage
.custom-container {
  @include make-container();
}
{{< /highlight >}}

For more information and examples on how to modify our Sass maps and variables, please refer to [the Sass section of the Grid documentation]({{< docsref "/layout/grid#sass" >}}).