Bootstrap Spacing: Margin, Padding and Gap

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

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You can assign responsive-friendly margin or padding values to an element or a subset of its sides with shorthand classes. Classes are built ranging from .25rem to 3rem.

Spacing utilities that apply to all breakpoints, from xs to xxl, have no breakpoint abbreviation in them.

Format of Class

The classes are named using the format {property}{sides}-{size}.

The property is one of:

  1. m - for classes that set margin
  2. p - for classes that set padding

The sides is one of:

  1. t - (top) for classes that set margin-top or padding-top
  2. b - (bottom) for classes that set margin-bottom or padding-bottom
  3. s - (start) for classes that set margin-left or padding-left in LTR, margin-right or padding-right in RTL
  4. e - (end) for classes that set margin-right or padding-right in LTR, margin-left or padding-left in RTL
  5. x - (horizontal) for classes that set both *-left and *-right
  6. y - (vertical) for classes that set both *-top and *-bottom
  7. blank - for classes that set a margin or padding on all 4 sides of the element

The size is one of:

  1. 0 - for classes that eliminate the margin or padding by setting it to 0
  2. 1 - for classes that set the margin or padding to $spacer * .25
  3. 2 - (by default) for classes that set the margin or padding to $spacer * .5
  4. 3 - (by default) for classes that set the margin or padding to $spacer
  5. 4 - (by default) for classes that set the margin or padding to $spacer * 1.5
  6. 5 - (by default) for classes that set the margin or padding to $spacer * 3
  7. auto - for classes that set the margin to auto

Horizontal Centering

Bootstrap 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.

For example,

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

Gap

When using display: grid or display: flex, you can use gap utilities on the parent element. This can save on having to add margin utilities to individual children of a grid or flex container. For example,

<div class="grid gap-3">
  <div class="p-2 g-col-6">Grid item 1</div>
  <div class="p-2 g-col-6">Grid item 2</div>
  <div class="p-2 g-col-6">Grid item 3</div>
  <div class="p-2 g-col-6">Grid item 4</div>
</div>

The row-gap sets the vertical space between children items. The column-gap sets the horizontal space between children items.