Bootstrap 4 Grid System

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

If you do not want to use all 12 columns individually, you can group the columns together to create wider columns:

The grid system is responsive, and the columns will re-arrange automatically depending on the screen size.

Make sure that the sum adds up to 12 or fewer (it is not required that you use all 12 available columns).

Grid Classes

The Bootstrap 4 grid system has five 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)

The classes above can be combined to create more dynamic and flexible layouts.

Tip: Each class scales up, so if you wish to set the same widths for sm and md, you only need to specify sm.

Basic Structure of a Bootstrap 4 Grid

The following is a basic structure of a Bootstrap 4 grid:

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 or xl, 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. three cols = 33.33% width to each col. four cols = 25% width, etc. You can also use .col-sm|md|lg|xl to make the columns responsive.

Below we have collected some examples of basic Bootstrap 4 grid layouts.

Three Equal Columns

The following example shows how to create three equal-width columns, on all devices and screen widths:

Responsive Columns

The following example shows how to create four equal-width columns starting at tablets and scaling to extra large desktops. On mobile phones or screens that are less than 576px wide, the columns will automatically stack on top of each other:

Two Unequal Responsive Columns

The following example shows how to get two various-width columns starting at tablets and scaling to large extra desktops:

Containers

You learned from the previous chapter that Bootstrap requires a containing element to wrap site contents.

Containers are used to pad the content inside of them, and there are two container classes available:

1. The .container class provides a responsive fixed width container
2. The .container-fluid class provides a full width container, spanning the entire width of the viewport

Fixed Container

Use the .container class to create a responsive, fixed-width container.

Note that its width (max-width) will change on different screen sizes:

Open the example below and resize the browser window to see that the container width will change at different breakpoints:

Fluid Container

Use the .container-fluid class to create a full width container, that will always span the entire width of the screen (width is always 100%):

Container Padding

By default, containers have 15px left and right padding, with no top or bottom padding. Therefore, we often use spacing utilities, such as extra padding and margins to make them look even better. For example, .pt-3 means “add a top padding of 16px”: