General
Grid system
Grid system
Responsive, mobile first fluid grid system.While Bootstrap uses ems or rems for defining most sizes, pxs 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.
Extra small <576px |
Small ≥576px |
Medium ≥768px |
Large ≥992px |
Extra large ≥1200px |
|
---|---|---|---|---|---|
Max container width | None (auto) | 540px | 720px | 960px | 1140px |
Class prefix | .col- |
.col-sm- |
.col-md- |
.col-lg- |
.col-xl- |
# of columns | 12 | ||||
Gutter width | 30px (15px on each side of a column) | ||||
Nestable | Yes | ||||
Column ordering | Yes |
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.
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.
<div class="container"> <div class="row"> <div class="col-sm"> One of three columns </div> <div class="col-sm"> One of three columns </div> <div class="col-sm"> One of three columns </div> </div> </div>
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
forwidth: 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. Thispadding
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 themargin
from rows andpadding
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 firstxs
breakpoint). - You can use predefined grid classes (like
.col-4
) or Sass mixins for more semantic markup.