Bootstrap/docs/layout/grid.md

layout	title	group
page	Grid system	layout

Bootstrap includes a powerful mobile-first grid system for building layouts of all shapes and sizes based on a 12 column layout. There are multiple tiers, one for each [media query range]({{ site.baseurl }}/layout/media-queries/), made available via our predefined classes or semantic mixins.

Here's how the grid system works:

• There are three major components—containers, rows, and columns.
• Containers—.container for fixed width or .container-fluid for full width—center your site's contents.
• Rows are horizontal groups of columns that clear floats (when not in [flexbox mode]({{ site.baseurl }}/getting-started/flexbox/)).
• Content should be placed within columns, and only columns may be immediate children of rows.
• You can use predefined grid classes or Sass mixins for more semantic markup.

Contents

• Will be replaced with the ToC, excluding the "Contents" header {:toc}

Quick start

• Example grid class
• Example mixins

Introduction

Grid systems are used for creating page layouts through a series of rows and columns that house your content. Here's how the Bootstrap grid system works:

• Rows must be placed within a .container (fixed-width) or .container-fluid (full-width) for proper alignment and padding.
• Use rows to create horizontal groups of columns.
• Content should be placed within columns, and only columns may be immediate children of rows.
• Predefined grid classes like .row and .col-xs-4 are available for quickly making grid layouts. Sass mixins can also be used for more semantic layouts.
• Columns create gutters (gaps between column content) via padding. That padding is offset in rows for the first and last column via negative margin on .rows.
• The negative margin is why the examples below are outdented. It's so that content within grid columns is lined up with non-grid content.
• Grid columns are created by specifying the number of twelve available columns you wish to span. For example, three equal columns would use three .col-xs-4.
• If more than 12 columns are placed within a single row, each group of extra columns will, as one unit, wrap onto a new line.
• Grid classes apply to devices with screen widths greater than or equal to the breakpoint sizes, and override grid classes targeted at smaller devices. Therefore, applying any .col-md- class to an element will not only affect its styling on medium devices but also on large devices if a .col-lg- class is not present.

Look to the examples for applying these principles to your code.

Grid options

See how aspects of the Bootstrap grid system work across multiple devices with a handy table.

	Extra small devices Portrait phones (<34em)	Small devices Landscape phones (≥34em)	Medium devices Tablets (≥48em)	Large devices Desktops (≥62em)	Extra large devices Desktops (≥75em)
Grid behavior	Horizontal at all times	Collapsed to start, horizontal above breakpoints
Container width	None (auto)	34rem	45rem	60rem	72.25rem
Class prefix	.col-xs-	.col-sm-	.col-md-	.col-lg-	.col-xl-
# of columns	12
Gutter width	30px (15px on each side of a column)
Nestable	Yes
Offsets	Yes
Column ordering	Yes

Sass mixins

When using Bootstrap's source Sass files, you have the option of using Sass variables and mixins to create custom, semantic, and responsive page layouts. Our prebuilt grid classes use these same variables and mixins to provide a whole suite of ready-to-use classes for fast responsive layouts.

Variables

Variables determine the number of columns, the gutter width, and the media query point at which to begin floating columns. We use these to generate the predefined grid classes documented above, as well as for the custom mixins listed below.

{% highlight scss %} $grid-breakpoints: ( // Extra small screen / phone xs: 0, // Small screen / phone sm: 34em, // Medium screen / tablet md: 48em, // Large screen / desktop lg: 62em, // Extra large screen / wide desktop xl: 75em ) !default;

$grid-columns: 12; $grid-gutter-width: 1.5rem; {% endhighlight %}

Mixins

Mixins are used in conjunction with the grid variables to generate semantic CSS for individual grid columns.

{% highlight scss %} // Creates a wrapper for a series of columns @mixin make-row($gutter: $grid-gutter-width) { margin-left: ($gutter / -2); margin-right: ($gutter / -2); @include clearfix(); }

// Make the element grid-ready (applying everything but the width) @mixin make-col($gutter: $grid-gutter-width) { position: relative; float: left; min-height: 1px; padding-left: ($gutter / 2); padding-right: ($gutter / 2); }

// Set a width (to be used in or out of media queries) @mixin make-col-span($columns) { width: percentage(($columns / $grid-columns)); }

// Get fancy by offsetting, or changing the sort order @mixin make-col-offset($columns) { margin-left: percentage(($columns / $grid-columns)); } @mixin make-col-push($columns) { left: percentage(($columns / $grid-columns)); } @mixin make-col-pull($columns) { right: percentage(($columns / $grid-columns)); } {% endhighlight %}

Example usage

You can modify the variables to your own custom values, or just use the mixins with their default values. Here's an example of using the default settings to create a two-column layout with a gap between.

See it in action in this rendered example.

{% highlight scss %} .container { max-width: 60em; @include make-container(); } .row { @include make-row(); } .content-main { @include make-col();

@media (max-width: 32em) { @include make-col-span(6); } @media (min-width: 32.1em) { @include make-col-span(8); } } .content-secondary { @include make-col();

@media (max-width: 32em) { @include make-col-span(6); } @media (min-width: 32.1em) { @include make-col-span(4); } } {% endhighlight %}

{% highlight html %}

...

...

{% endhighlight %}

Predefined classes

In addition to our semantic mixins, Bootstrap includes an extensive set of prebuilt classes for quickly creating grid columns. It includes options for device-based column sizing, reordering columns, and more.

Example: Stacked-to-horizontal

Using a single set of .col-md-* grid classes, you can create a basic grid system that starts out stacked on mobile devices and tablet devices (the extra small to small range) before becoming horizontal on desktop (medium) devices. Place grid columns in any .row.

{% example html %}

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-1

.col-md-8

.col-md-4

.col-md-4

.col-md-4

.col-md-4

.col-md-6

.col-md-6

{% endexample %}

Example: Fluid container

Turn any fixed-width grid layout into a full-width layout by changing your outermost .container to .container-fluid.

{% highlight html %}

...

{% endhighlight %}

Example: Mobile and desktop

Don't want your columns to simply stack in smaller devices? Use the extra small and medium device grid classes by adding .col-xs-* and .col-md-* to your columns. See the example below for a better idea of how it all works.

{% example html %}

.col-xs-12 .col-md-8

.col-xs-6 .col-md-4

.col-xs-6 .col-md-4

.col-xs-6 .col-md-4

.col-xs-6 .col-md-4

.col-xs-6

.col-xs-6

{% endexample %}

Example: Mobile, tablet, desktop

Build on the previous example by creating even more dynamic and powerful layouts with tablet .col-sm-* classes.

{% example html %}

.col-xs-12 .col-sm-6 .col-md-8

.col-xs-6 .col-md-4

.col-xs-6 .col-sm-4

.col-xs-6 .col-sm-4

.col-xs-6 .col-sm-4

{% endexample %}

Example: Column wrapping

If more than 12 columns are placed within a single row, each group of extra columns will, as one unit, wrap onto a new line.

{% example html %}

.col-xs-9

.col-xs-4
Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.

.col-xs-6
Subsequent columns continue along the new line.

{% endexample %}

Example: Responsive column resets

With the four tiers of grids available you're bound to run into issues where, at certain breakpoints, your columns don't clear quite right as one is taller than the other. To fix that, use a combination of a .clearfix and our responsive utility classes.

{% example html %}

.col-xs-6 .col-sm-3

.col-xs-6 .col-sm-3

.col-xs-6 .col-sm-3

.col-xs-6 .col-sm-3

{% endexample %}

In addition to column clearing at responsive breakpoints, you may need to reset offsets, pushes, or pulls. See this in action in the grid example.

{% example html %}

.col-sm-5 .col-md-6

.col-sm-5 .col-sm-offset-2 .col-md-6 .col-md-offset-0

.col-sm-6 .col-md-5 .col-lg-6

.col-sm-6 .col-md-5 .col-md-offset-2 .col-lg-6 .col-lg-offset-0

{% endexample %}

Example: Offsetting columns

Move columns to the right using .col-md-offset-* classes. These classes increase the left margin of a column by * columns. For example, .col-md-offset-4 moves .col-md-4 over four columns.

{% example html %}

.col-md-4

.col-md-4 .col-md-offset-4

.col-md-3 .col-md-offset-3

.col-md-3 .col-md-offset-3

.col-md-6 .col-md-offset-3

{% endexample %}

Example: Nesting columns

To nest your content with the default grid, add a new .row and set of .col-sm-* columns within an existing .col-sm-* column. 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).

{% example html %}

Level 1: .col-sm-9

Level 2: .col-xs-8 .col-sm-6

Level 2: .col-xs-4 .col-sm-6

{% endexample %}

Example: Column ordering

Easily change the order of our built-in grid columns with .col-md-push-* and .col-md-pull-* modifier classes.

{% example html %}

.col-md-9 .col-md-push-3

.col-md-3 .col-md-pull-9

{% endexample %}