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margin-block

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨April 2021⁩.

* Some parts of this feature may have varying levels of support.

The margin-block CSS shorthand property defines the logical block start and end margins of an element, which maps to physical margins depending on the element's writing mode, directionality, and text orientation.

Try it

margin-block: 10px 20px;
writing-mode: horizontal-tb;

margin-block: 20px 40px;
writing-mode: vertical-rl;

margin-block: 5% 20%;
writing-mode: horizontal-tb;

margin-block: 1rem auto;
writing-mode: vertical-lr;

<section id="default-example">
  <div id="container">
    <div class="row">One</div>
    <div class="row transition-all" id="example-element">Two</div>
    <div class="row">Three</div>
  </div>
</section>

#container {
  width: 300px;
  height: 200px;
  display: flex;
  align-content: flex-start;
  flex-direction: column;
  justify-content: flex-start;
}

.row {
  height: 33.33%;
  display: inline-block;
  border: solid #ce7777 10px;
  background-color: #2b3a55;
  color: white;
  flex-shrink: 0;
}

#example-element {
  border: solid 10px #ffbf00;
  background-color: #2b3a55;
}

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

/* <length> values */
margin-block: 10px 20px; /* An absolute length */
margin-block: 1em 2em; /* relative to the text size */
margin-block: 5% 2%; /* relative to the nearest block container's width */
margin-block: 10px; /* sets both start and end values */
margin-block: anchor-size(inline);
margin-block: calc(anchor-size(width) / 4) 1em;

/* Keyword values */
margin-block: auto;

/* Global values */
margin-block: inherit;
margin-block: initial;
margin-block: revert;
margin-block: revert-layer;
margin-block: unset;

This property corresponds to the margin-top and margin-bottom, or the margin-right and margin-left properties, depending on the values defined for writing-mode, direction, and text-orientation.

The margin-block property may be specified using one or two values.

When one value is specified, it applies the same margin to both start and end.
When two values are specified, the first margin applies to the start, the second to the end.

Values

The margin-block property takes the same values as the margin property.

Formal definition

Initial value	as each of the properties of the shorthand: `margin-block-start`: `0` `margin-block-end`: `0`
Applies to	same as `margin`
Inherited	no
Percentages	depends on layout model
Computed value	as each of the properties of the shorthand: `margin-block-start`: if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, `auto` `margin-block-end`: if specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, `auto`
Animation type	a length

Formal syntax

margin-block = 
  <'margin-top'>{1,2}  

<margin-top> = 
  <length-percentage>  |
  auto                 |
  <anchor-size()>      

<length-percentage> = 
  <length>      |
  <percentage>  

<anchor-size()> = 
  anchor-size( [ <anchor-name> || <anchor-size> ]? , <length-percentage>? )  

<anchor-name> = 
  <dashed-ident>  

<anchor-size> = 
  width        |
  height       |
  block        |
  inline       |
  self-block   |
  self-inline

Examples

Setting block start and end margins

CSS

div {
  background-color: yellow;
  width: 120px;
  height: auto;
  border: 1px solid green;
}

p {
  margin: 0;
  margin-block: 20px 40px;
  background-color: tan;
}

.verticalExample {
  writing-mode: vertical-rl;
}

HTML

<div>
  <p>Example text</p>
</div>
<div class="verticalExample">
  <p>Example text</p>
</div>

Result

Specifications

Specification
CSS Logical Properties and Values Level 1> # propdef-margin-block>

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	WebView on iOS
`margin-block`	87	87	66	73	14.1	87	66	62	14.5	14.0	87	14.5
`anchor-size`	132	132	No	117	26	132	No	87	26	No	132	26