Margins and Paddings

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 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 * .25
• 2 - (by default) for classes that set the margin or padding to $spacer * .5
• 3 - (by default) for classes that set the margin or padding to $spacer
• 4 - (by default) for classes that set the margin or padding to $spacer * 1.5
• 5 - (by default) for classes that set the margin or padding to $spacer * 3
• auto - for classes that set the margin to auto

(You can add more sizes by adding entries to the $spacers Sass map variable.)

Horizontal centering

Additionally, Bootstrap also includes an .mx-auto class for horizontally centering fixed-width block level content—that is, content that has display: block and a width set—by setting the horizontal margins to auto.

  <div class="mx-auto" style="width: 200px;">
    Centered element
  </div>