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Cards are a good way to display content composed of different types of objects. They’re well-suited for presenting similar objects whose size or supported actions vary, like headings and photos with captions.

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Use card groups to render equal height cards without gutters between the cards. Use .card-deck for cards that aren’t attached to each another.

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Same Height

A frequent problem occurs when you have multiple items in a row with content of varying height. Thanks to flexbox (and display:table) we now have equal height cards!



Flexbox provides simpler, more flexible layout options like vertical centering.


Simply set the $enable-flex variable to enable flexbox in Bootstrap 4.

It's Modern

Introduced in CSS3, flexbox won't work in older browsers like IE9.

Now there are 5 Breakpoints

To accomodate a variety of devices and screen widths


<34 em


≥34 em


≥48 em


≥62 em


≥75 em

Fonts got larger


Text is larger in Bootstrap 4. The default font size is now 16px. There are also new "Display headings" that really stand out. The new `em` based sizing is cool too.


The new Bootstrap 4 .navbar code is lighter. You can make it responsive using the Collapse component and .navbar-toggleable-* classes that enable you to control the breakpoint.

RIP icons, affix, etc..

Some components have been removed from Bootstrap 4. The Glyphicons icon fonts are no longer included, but it's easy to utilize another font like FontAwesome, Octicons or Ionicons. The Affix jQuery plugin has also been dropped. The new recommendation is to use HTML5 position: sticky or a sticky polyfill instead.

  • text-capitalize Capitalize each word
  • text-uppercase Uppercase text
  • text-lowercase There is lowercase too
  • text-truncate some longer text that won't wrap and will truncate with ellipsis at the end.
Migration tips
  • well = card card-block
  • panel panel-default = card
  • text-center = text-xs-center
  • text-right = text-xs-right
  • pull-right = pull-xs-right
  • img-responsive = img-fluid
  • list-inline > li = list-inline-item
  • add nav-item to nav navbar > li
  • add nav-link to nav navbar > li > a
  • the active class is added to nav-item for scrollspy
  • carousel-inner > item = carousel-item
  • table-condensed = table-sm
  • input-lg = form-control-lg
  • input-sm = form-control-sm
Here's a handy Bootstrap 3 to 4 upgrade tool to convert your code!

Handy utilities

Several simple, but useful utility classes have been added like text, margin and padding helpers. There are also contextual colors and responsive utility classes to hide content on specific breakpoints. There's even a new fluid Jumbotron!

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