Introduction

The margin CSS property is commonly used in CSS to add space around an element.

Remember:

  • margin adds space around an element border
  • padding adds space inside an element border

Specific margin properties

margin has 4 related properties that alter the margin of a single margin at once:

  • margin-top
  • margin-right
  • margin-bottom
  • margin-left

The usage of those is very simple and cannot be confused, for example:

margin-left: 30px;
margin-right: 3em;

Using margin with different values

margin is a shorthand to specify multiple margins at the same time, and depending on the number of values entered, it behaves differently.

1 value

Using a single value applies that to all the margins: top, right, bottom, left.

margin: 20px;

2 values

Using 2 values applies the first to bottom & top, and the second to left & right.

margin: 20px 10px;

3 values

Using 3 values applies the first to top, the second to left & right, the third to bottom.

margin: 20px 10px 30px;

4 values

Using 4 values applies the first to top, the second to right, the third to bottom, the fourth to left.

margin: 20px 10px 5px 0px;

So, the order is top-right-bottom-left.

Values accepted

margin accepts values expressed in any kind of length unit, the most common ones are px, em, rem, but many others exist.

It also accepts percentage values, and the special value auto.

Using auto to center elements

auto can be used to tell the browser to select automatically a margin, and it’s most commonly used to center an element in this way:

margin: 0 auto;

As said above, using 2 values applies the first to bottom & top, and the second to left & right.

The modern way to center elements is to use Flexbox, and its justify-content: center; directive.

Older browsers of course do not implement Flexbox, and if you need to support them margin: 0 auto; is still a good choice.