`s and classes) and BootstrapVue functional layout components. ## How it works Bootstrap's grid system uses a series of containers, rows, and columns to layout and align content. It's built with [flexbox](https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Flexible_Box_Layout/Basic_Concepts_of_Flexbox) and is fully responsive. Below is an example and an in-depth look at how the grid comes together. ```html

1 of 3

2 of 3

3 of 3

``` The above example creates three equal-width columns on small, medium, large, and extra large devices using Bootstrap v4's predefined grid classes. Those columns are centered in the page with the parent `.container`. Breaking it down, here's how it works: - Containers provide a means to center and horizontally pad your site's contents. Use `` for a responsive pixel width or `` for `width: 100%` across all viewport and device sizes. - Rows are wrappers for columns. Each column has horizontal `padding` (called a gutter) for controlling the space between them. This `padding` is then counteracted on the rows with negative margins. This way, all the content in your columns is visually aligned down the left side. - In a grid layout, content must be placed within columns and only columns may be immediate children of rows. - Thanks to flexbox, grid columns without a set width will automatically layout with equal widths. For example, four instances of `` will each automatically be 25% wide for small breakpoints. - Column prop `cols` indicates the number of columns you'd like to use out of the possible 12 per row regardless of breakpoint (starting at breakpoint `xs`). So, if you want three equal-width columns at any breakpoint, you can use ``. - Column props `sm`, `md`, `lg`, `xl` indicate the number of columns you'd like to use out of the possible 12 per row, at the various breakpoints. So, if you want three equal-width columns at breakpoint `sm`, you can use ``. the special value `auto` can be used to take up the remaining available column space in a row. - Column `width`s are set in percentages, so they're always fluid and sized relative to their parent element. - Columns have horizontal `padding` to create the gutters between individual columns, however, you can remove the `margin` from `` and `padding` from `` by setting the `no-gutters` prop on ``. - To make the grid responsive, there are five grid breakpoints, one for each responsive breakpoint: all breakpoints (extra small), small, medium, large, and extra large. - Grid breakpoints are based on minimum width media queries, meaning **they apply to that one breakpoint and all those above it** (e.g., `` applies to small, medium, large, and extra large devices, but not the first `xs` breakpoint). - You can use predefined grid classes or Sass mixins for more semantic markup. Be aware of the limitations and [bugs around flexbox](https://github.com/philipwalton/flexbugs), like the [inability to use some HTML elements as flex containers](https://github.com/philipwalton/flexbugs#flexbug-9). ## Containers `` Containers (``) are the most basic layout element in Bootstrap and is **required when using the grid system**. Choose from a responsive, fixed-width container (meaning its max-width changes at each breakpoint) by default, or fluid-width (meaning it's 100% wide all the time) by setting 'fluid' prop. While containers can be nested, most layouts do not require a nested container. **Fixed width container, based on viewport breakpoints:** ```html ``` **Fluid container which is always 100% width, regardless of viewport breakpoint:** ```html ``` ## Rows `` and `` `` components must be placed inside a `` component, or an element (such as a `

`) that has the class `container` or `container-fluid` applied to it. You can remove the margin from `` and padding from `` by setting the `no-gutters` prop on ``. Or, for compact margins (smaller gutters between columns), use the `` component, which is typically used in [forms](/docs/components/form). ## Columns `` `` Must be placed inside a `` component, or an element (such as a `

`) that has the class `row` applied to it, or - in the case of [forms](/docs/components/form) - inside a `` component to obtain columns with more compact margins. ## Grid options While Bootstrap uses `em`s or `rem`s for defining most sizes, `px`s are used for grid breakpoints and container widths. This is because the viewport width is in pixels and does not change with the [font size](https://drafts.csswg.org/mediaqueries-3/#units). See how aspects of the Bootstrap grid system work across multiple devices with a handy table.

	Extra small `<576px`	Small `≥576px`	Medium `≥768px`	Large `≥992px`	Extra large `≥1200px`
Max container width	None (auto)	540px	720px	960px	1140px
Prop	`cols="*"`	`sm="*"`	`md="*"`	`lg="*"`	`xl="*"`
# of columns	12
Gutter width	30px (15px on each side of a column)
Nestable	Yes
Offset	`offset="*"`	`offset-sm="*"`	`offset-md="*"`	`offset-lg="*"`	`offset-xl="*"`
Order	`order="*"`	`order-sm="*"`	`order-md="*"`	`order-lg="*"`	`order-xl="*"`

Note: there is no `xs` prop. The `cols` prop refers to the `xs` (smallest) breakpoint. ## Auto-layout columns Utilize breakpoint-specific column classes for easy column sizing without an explicit numbered prop like ``. ### Equal-width columns For example, here are two grid layouts that apply to every device and viewport, from `xs` to `xl`. Add any number of unit-less classes for each breakpoint you need and every column will be the same width. ```html

1 of 2

2 of 2

1 of 3

2 of 3

3 of 3

``` ### Equal-width multi-line Create equal-width columns that span multiple lines by inserting a `.w-100` where you want the columns to break to a new line. Make the breaks responsive by mixing `.w-100` with some [responsive display utilities](https://getbootstrap.com/docs/4.3/utilities/display/). There was a [Safari flexbox bug](https://github.com/philipwalton/flexbugs#flexbug-11) that prevented this from working without an explicit `flex-basis` or `border`. There are workarounds for older browser versions, but they shouldn't be necessary if your target browsers don't fall into the buggy versions. ```html

Column

``` ### Setting one column width Auto-layout for flexbox grid columns also means you can set the width of one column and have the sibling columns automatically resize around it. You may use predefined grid classes (as shown below), grid mixins, or inline widths. Note that the other columns will resize no matter the width of the center column. ```html

1 of 3

2 of 3 (wider)

3 of 3

1 of 3

2 of 3 (wider)

3 of 3

``` ### Variable width content Use `{breakpoint}="auto"` props to size columns based on the natural width of their content. ```html

1 of 3

Variable width content

3 of 3

1 of 3

Variable width content

3 of 3

``` ## Responsive classes Bootstrap's grid includes five tiers of predefined classes for building complex responsive layouts. Customize the size of your columns on extra small, small, medium, large, or extra large devices however you see fit. ### All breakpoints For grids that are the same from the smallest of devices to the largest, use the `col` and `cols="*"` props. Specify a number of `cols` when you need a particularly sized column; otherwise, feel free to stick to `col` (which is applied automatically if no `cols` are specified). ```html

col

col-8

col-4

``` ### Stacked to horizontal Using a single set of `sm="*"` or `sm` (boolean for equal width @sm) props, you can create a basic grid system that starts out stacked on extra small devices before becoming horizontal on desktop (medium) devices. ```html

col-sm-8

col-sm-4

col-sm

``` ### Mix and match Don't want your columns to simply stack in some grid tiers? Use a combination of different props for each tier as needed. See the example below for a better idea of how it all works. ```html

cols="12" md="8"

cols="6" md="4"

cols="6"

``` ## Alignment Use flexbox alignment utilities to vertically and horizontally align columns. ### Vertical alignment ```html

One of three columns

``` ```html

One of three columns

``` ### Horizontal alignment ```html

One of two columns

``` ## Reordering ### Ordering columns Use `order-*` props for controlling the visual order of your content. These props are responsive, so you can set the order by breakpoint (e.g., `order="1" order-md="2"`). Includes support for 1 through 12 across all five grid tiers. `` defaults to an order value of `0`. ```html

First in DOM, no order applied

Second in DOM, with a larger order

Third in DOM, with an order of 1

First in DOM, with order of 6

Second in DOM, with an order of 1

Third in DOM, no order applied

``` Ordering is controlled by flexbox's CSS style `order`. ### Offsetting columns You can offset grid columns in two ways: our responsive `offset-*` props or the [margin](/docs/reference/spacing-classes) utility classes. Grid `offset-*` props are sized to match columns while margins utility classes are more useful for quick layouts where the width of the offset is variable. ```html

md="4"

md="4" offset-md="4"

md="3" offset-md="3"

md="6" offset-md="3"

``` In addition to column clearing at responsive breakpoints, you may need to reset offsets by setting the offset to `0` at a larger breakpoint: ```html

sm="5" md="6"

sm="5" offset-sm="2" md="6" offset-md="0"

sm="6" md="5" lg="6"

sm="6" md="5" offset-md="2" col-lg="6" offset-lg="0"

``` ### Margin utilities on columns With the move to flexbox in Bootstrap v4, you can use [margin and spacing](/docs/reference/spacing-classes) utility classes like `.mr-auto` to force sibling columns away from one another. ```html

md="4"

md="4" .ml-auto

md="3" .ml-md-auto

cols="auto" .mr-auto

cols="auto"

``` ## Nesting grids To nest your content with the default grid, add a new `` and set of `` components within an existing `` component. Nested rows should include a set of columns that add up to 12 or fewer (it is not required that you use all 12 available columns). ```html

Level 1: sm="9"

Level 2: cols="8" sm="6"

Level 2: cols="4" sm="6"

```