Bootstrap 4 Grid Stacked-to-horizontal
Bootstrap 4 Grid Example: Stacked-to-horizontal
We will create a basic grid system that starts out stacked on extra small devices, before becoming horizontal on larger devices.
The following example shows a simple "stacked-to-horizontal" two-column layout, meaning it will result in a 50%/50% split on all screens, except for extra small screens, which it will automatically stack (100%):
Example: Stacked-to-horizontal
 <div class="container">
  <div class="row">
      <div class="col-sm-6 bg-success">
      <p>Lorem ipsum...</p>
    </div>
      <div class="col-sm-6 bg-warning">
      <p>Sed ut perspiciatis...</p>
    </div>
  </div>
 </div>
Try it Yourself »Tip: The numbers in the .col-sm-* classes indicates how many columns the 
div should 
span (out of 12). So, .col-sm-1 spans 1 column, .col-sm-4 spans 4 columns, 
.col-sm-6 spans 6 columns, etc.
Note: 
  Make sure that the sum adds up to 12 or fewer (it is not required that you use 
  all 12 available columns):
Tip: You can turn any fixed-width layout into a full-width layout by changing 
the .container class to .container-fluid:
Example: Fluid container
 <div class="container-fluid">
  <div class="row">
      <div class="col-sm-6">
      <p>Lorem ipsum...</p>
    </div>
      <div class="col-sm-6">
      <p>Sed ut perspiciatis...</p>
    </div>
  </div>
</div>
Try it Yourself »
Auto Layout Columns
In Bootstrap 4, there is an easy way to create equal width columns for all devices: just remove the number from .col-size-* and only use the .col-size class on a specified number of 
col elements. Bootstrap will recognize how many columns there 
are, and each column will get the same width. The size classes 
determines when the columns should be responsive:
  <!-- Two columns: 50% width on all screens, except for extra small (100% 
  width) -->
<div class="row">
  <div class="col-sm">1 of 
  2</div>
 
<div class="col-sm">2 of 2</div>
</div>
<!-- Four 
  columns: 25% width on all screens, except for extra small (100% width)-->
<div class="row">
  <div class="col-sm">1 of 4</div>
 
<div class="col-sm">2 of 4</div>
  <div class="col-sm">3 
  of 4</div>
  <div class="col-sm">4 of 4</div>
  </div>