Bootstrap includes a wide range of shorthand responsive margin utility classes to modify an element’s appearance.

Detailed documentation and more examples of Bootstrap grid you can find in our Bootstrap Spacing Docs.

Example: Usage mr-* class.

m - for classes that set margin

r - for classes that set margin-right

.mr-0 No margin 0 - for classes that eliminate the margin by setting it to 0
.mr-1 No margin 1 - (by default) for classes that set the margin to $spacer-x * .25 or $spacer-y * .25
.mr-2 No margin 2 - (by default) for classes that set the margin to $spacer-x * .5 or $spacer-y * .5
.mr-3 No margin 3 - (by default) for classes that set the margin or padding to $spacer-x or $spacer-y
.mr-4 No margin 4 - (by default) for classes that set the margin to $spacer-x * 1.5 or $spacer-y * 1.5
.mr-5 No margin 5 - (by default) for classes that set the margin to $spacer-x * 3 or $spacer-y * 3

Notation

Spacing utilities that apply to all breakpoints, from xs to xl, have no breakpoint abbreviation in them. This is because those classes are applied from min- width: 0 and up, and thus are not bound by a media query. The remaining breakpoints, however, do include a breakpoint abbreviation.

The classes are named using the format {property}{sides}-{size} for xs and {property}{sides}-{breakpoint}-{size} for sm, md, lg, and xl.

Where property is one of:

  • m - for classes that set margin
  • p - for classes that set padding

Where sides is one of:

  • t - for classes that set margin-top or padding-top
  • b - for classes that set margin-bottom or padding-bottom
  • l - for classes that set margin-left or padding-left
  • r - for classes that set margin-right or padding-right
  • x - for classes that set both *-left and *-right
  • y - for classes that set both *-top and *-bottom
  • blank - for classes that set a margin or padding on all 4 sides of the element

Where breakpoint is one of:

  • sm
  • md
  • lg
  • xl

Where size is one of:

  • 0 - for classes that eliminate the margin or padding by setting it to 0
  • 1 - (by default) for classes that set the margin or padding to $spacer-x * .25 or $spacer-y * .25
  • 2 - (by default) for classes that set the margin or padding to $spacer-x * .5 or $spacer-y * .5
  • 3 - (by default) for classes that set the margin or padding to $spacer-x or $spacer-y
  • 4 - (by default) for classes that set the margin or padding to $spacer-x * 1.5 or $spacer-y * 1.5
  • 5 - (by default) for classes that set the margin or padding to $spacer-x * 3 or $spacer-y * 3
(You can add more sizes by adding entries to the $spacers Sass map variable.)