The effect of the CSS margin-bottom property on the element boxThe margin-bottom CSS property of an element sets the margin space required on the bottom of an element. A negative value is also allowed.

This property has no effect on non-replaced inline elements, like <tt> or <span>.

  • Initial value 0
  • Applies to all elements except elements with table display types other than table-caption, table and inline-table. It also applies to ::first-letter.
  • Inherited no
  • Percentages refer to the width of the containing block
  • Media visual
  • Computed value the percentage as specified or the absolute length
  • Animatable yes, as a length
  • Canonical order the unique non-ambiguous order defined by the formal grammar


/* <length> values */
margin-bottom: 10px;        /* An absolute length */
margin-bottom: 1em;         /* A length relative to the text size */
margin-bottom: 5%;          /* A margin relative to the nearest block container's width */

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

/* Global values */
margin-bottom: inherit;
margin-bottom: initial;
margin-bottom: unset;


Specifies a fixed width. See <length> for possible values.
A <percentage> always relative to the width of the containing block.
See margin.

Formal syntax

<length> | <percentage> | auto



<div class="container">
<div class="box0">Box 0</div>
<div class="box1">Box 1</div>
<div class="box2">Box one's negative margin pulls me up</div>


CSS for divs to set margin-bottom and height

.box0 {
.box1 {
.box2 {
    border:1px dashed black;
    border-width:1px 0;

Some definations for container and divs so margins' effects can be seen more clearly

.container {
    border:1px solid black;
div {


Specification Status Comment
CSS Basic Box Model
The definition of 'margin-bottom' in that specification.
Working Draft No significant change.
CSS Transitions
The definition of 'margin-bottom' in that specification.
Working Draft Defines margin-bottom as animatable.
CSS Level 2 (Revision 1)
The definition of 'margin-bottom' in that specification.
Recommendation Removes its effect on inline elements.
CSS Level 1
The definition of 'margin-bottom' in that specification.
Recommendation Initial definition.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 1.0 1.0 (1.7 or earlier) 3.0 3.5 1.0 (85)
auto value 1.0 1.0 (1.7 or earlier) 6.0 (strict mode) 3.5 1.0 (85)
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 1.0 1.0 (1) 6.0 6.0 1.0

See also

Document Tags and Contributors

Last updated by: Sebastianz,
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