Use our powerful mobile-first flexbox grid to build layouts of all shapes and sizes thanks to a twelve column system, five default responsive tiers, Sass variables and mixins, and dozens of predefined classes.
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
and is fully responsive. Below is an example and an in-depth look at how the grid comes together.
The above example creates three equal-width columns on small, medium, large, and extra large devices using our 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
.container
for a responsive pixel width or
.container-fluid
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 specified
width
will automatically layout as equal width columns. For example, four instances of
.col-sm
will each automatically be 25% wide from the small breakpoint and up. See the
auto-layout columns
section for more examples.
Column classes indicate the number of columns you’d like to use out of the possible 12 per row. So, if you want three equal-width columns across, you can use
.col-4
.
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 rows and
padding
from columns with
.no-gutters
on the
.row
.
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.,
.col-sm-4
applies to small, medium, large, and extra large devices, but not the first
xs
breakpoint).
You can use predefined grid classes (like
.col-4
) or
Sass mixins
for more semantic markup.
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
.
See how aspects of the Bootstrap grid system work across multiple devices with a handy table.
Auto-layout columns
Utilize breakpoint-specific column classes for easy column sizing without an explicit numbered class like
.col-sm-6
.
Equal-width
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.
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.
<divclass="container"><divclass="row justify-content-md-center"><divclass="col col-lg-2">
1 of 3
<divclass="col-md-auto">
Variable width content
<divclass="col col-lg-2">
3 of 3
<divclass="row"><divclass="col">
1 of 3
<divclass="col-md-auto">
Variable width content
<divclass="col col-lg-2">
3 of 3
Equal-width multi-row
Create equal-width columns that span multiple rows by inserting a .w-100 where you want the columns to break to a new line. Make the breaks responsive by mixing the .w-100 with some responsive display utilities.
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 .col-* classes. Specify a numbered class when you need a particularly sized column; otherwise, feel free to stick to .col.
Don’t want your columns to simply stack in some grid tiers? Use a combination of different classes for each tier as needed. See the example below for a better idea of how it all works.
.col-6
<!-- Stack the columns on mobile by making one full-width and the other half-width --><divclass="row"><divclass="col-12 col-md-8">.col-12 .col-md-8</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div><!-- Columns start at 50% wide on mobile and bump up to 33.3% wide on desktop --><divclass="row"><divclass="col-6 col-md-4">.col-6 .col-md-4</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div><divclass="col-6 col-md-4">.col-6 .col-md-4</div><!-- Columns are always 50% wide, on mobile and desktop --><divclass="row"><divclass="col-6">.col-6</div><divclass="col-6">.col-6</div>
Alignment
Use flexbox alignment utilities to vertically and horizontally align columns.
Vertical alignment
No gutters
The gutters between columns in our predefined grid classes can be removed with .no-gutters. This removes the negative margins from .row and the horizontal padding from all immediate children columns.
Here’s the source code for creating these styles. Note that column overrides are scoped to only the first children columns and are targeted via attribute selector. While this generates a more specific selector, column padding can still be further customized with spacing utilities.
Need an edge-to-edge design? Drop the parent .container or .container-fluid.
In practice, here’s how it looks. Note you can continue to use this with all other predefined grid classes (including column widths, responsive tiers, reorders, and more).
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.
.col-9
.col-4 Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.
.col-6 Subsequent columns continue along the new line.
<divclass="row"><divclass="col-9">.col-9</div><divclass="col-4">.col-4<br>Since 9 + 4 = 13 > 12, this 4-column-wide div gets wrapped onto a new line as one contiguous unit.</div><divclass="col-6">.col-6<br>Subsequent columns continue along the new line.</div>
Column breaks
Breaking columns to a new line in flexbox requires a small hack: add an element with width: 100% wherever you want to wrap your columns to a new line. Normally this is accomplished with multiple .rows, but not every implementation method can account for this.
<divclass="row"><divclass="col-6 col-sm-3">.col-6 .col-sm-3</div><divclass="col-6 col-sm-3">.col-6 .col-sm-3</div><!-- Force next columns to break to new line --><divclass="w-100"></div><divclass="col-6 col-sm-3">.col-6 .col-sm-3</div><divclass="col-6 col-sm-3">.col-6 .col-sm-3</div>
<divclass="row"><divclass="col-6 col-sm-4">.col-6 .col-sm-4</div><divclass="col-6 col-sm-4">.col-6 .col-sm-4</div><!-- Force next columns to break to new line at md breakpoint and up --><divclass="w-100 d-none d-md-block"></div><divclass="col-6 col-sm-4">.col-6 .col-sm-4</div><divclass="col-6 col-sm-4">.col-6 .col-sm-4</div>
Reordering
Order classes
Use .order- classes for controlling the visual order of your content. These classes 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.
Offsetting columns
You can offset grid columns in two ways: our responsive .offset- grid classes and our margin utilities. Grid classes are sized to match columns while margins are more useful for quick layouts where the width of the offset is variable.
Offset classes
Move columns to the right using .offset-md-* classes. These classes increase the left margin of a column by * columns. For example, .offset-md-4 moves .col-md-4 over four 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).
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 predefined grid classes use these same variables and mixins to provide a whole suite of ready-to-use classes for fast responsive layouts.
Variables
Variables and maps 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.
Mixins are used in conjunction with the grid variables to generate semantic CSS for individual grid columns.
// Creates a wrapper for a series of columns@includemake-row();// Make the element grid-ready (applying everything but the width)@includemake-col-ready();@includemake-col($size,$columns:$grid-columns);// Get fancy by offsetting, or changing the sort order@includemake-col-offset($size,$columns:$grid-columns);
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.
Using our built-in grid Sass variables and maps, it’s possible to completely customize the predefined grid classes. Change the number of tiers, the media query dimensions, and the container widths—then recompile.
Columns and gutters
The number of grid columns can be modified via Sass variables. $grid-columns is used to generate the widths (in percent) of each individual column while $grid-gutter-width allows breakpoint-specific widths that are divided evenly across padding-left and padding-right for the column gutters.
Moving beyond the columns themselves, you may also customize the number of grid tiers. If you wanted just four grid tiers, you’d update the $grid-breakpoints and $container-max-widths to something like this:
When making any changes to the Sass variables or maps, you’ll need to save your changes and recompile. Doing so will output a brand new set of predefined grid classes for column widths, offsets, and ordering. Responsive visibility utilities will also be updated to use the custom breakpoints. Make sure to set grid values in px (not rem, em, or %).
