Bootstrap's grid system is built with flexbox and allows up to 12 columns across the page.

Grid Classes

The Bootstrap 5 grid system has six classes:

• .col- (extra small devices - screen width less than 576px)
• .col-sm- (small devices - screen width equal to or greater than 576px)
• .col-md- (medium devices - screen width equal to or greater than 768px)
• .col-lg- (large devices - screen width equal to or greater than 992px)
• .col-xl- (xlarge devices - screen width equal to or greater than 1200px)
• .col-xxl- (xxlarge devices - screen width equal to or greater than 1400px)

Basic Structure of a Bootstrap 5 Grid

<!-- Control the column width, and how they should appear on different devices -->
<div class="row">
  <div class="col-*-*"></div>
  <div class="col-*-*"></div>
</div>
<div class="row">
  <div class="col-*-*"></div>
  <div class="col-*-*"></div>
  <div class="col-*-*"></div>
</div>

<!-- Or let Bootstrap automatically handle the layout -->
<div class="row">
  <div class="col"></div>
  <div class="col"></div>
  <div class="col"></div>
</div>

First example:

create a row (<div class="row">). Then, add the desired number of columns (tags with appropriate .col-*-* classes).

The first star (*) represents the responsiveness: sm, md, lg, xl or xxl, while the second star represents a number, which should add up to 12 for each row.

Second example:

instead of adding a number to each col, let bootstrap handle the layout, to create equal width columns: two "col" elements = 50% width to each col, while three cols = 33.33% width to each col. Four cols = 25% width, etc. You can also use .col-sm|md|lg|xl|xxl to make the columns responsive.