While Bootstrap uses
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
| Extra large
|Max container width||None (auto)||540px||720px||960px||1140px|
|# of columns||12|
|Gutter width||30px (15px on each side of a column)|
For example, here are two grid layouts that apply to every device and viewport, from
xl. Add any number of unit-less classes for each breakpoint you need and every column will be the same width.
Using a single set of
.col-md-* grid classes, you can create a default 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
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-md-* to your columns. See the example below for a better idea of how it all works.
Example: Mobile, tablet, desktops
Build on the previous example by creating even more dynamic and powerful layouts with tablet
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.
Resize your viewport or check it out on your phone for an example.
Move columns to the right using
.offset-md--* classes. These classes increase the left margin of a column by
* columns. For example,
.col-md-4 over four columns.