bottom

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

The bottom CSS property participates in setting the vertical position of a positioned element. This inset property has no effect on non-positioned elements.

Try it

The effect of bottom depends on how the element is positioned (i.e., the value of the position property):

  • When position is set to absolute or fixed, the bottom property specifies the distance between the outer edge of the element's bottom margin and the outer edge of the containing block's bottom padding, or, in the case of anchor positioned elements when the anchor() function is used within the value, relative to the position of the specified <anchor-side> edge. The bottom property is compatible with the top, bottom, start, end, self-start, self-end, center, and <percentage> values.
  • When position is set to relative, the bottom property specifies the distance the element's bottom edge is moved above its normal position.
  • When position is set to sticky, the bottom property is used to compute the sticky-constraint rectangle.
  • When position is set to static, the bottom property has no effect.

When both top and bottom are specified, position is set to absolute or fixed, and height is unspecified (either auto or 100%) both the top and bottom distances are respected. In all other situations, if height is constrained in any way or position is set to relative, the top property takes precedence and the bottom property is ignored.

Syntax

css
/* <length> values */
bottom: 3px;
bottom: 2.4em;
bottom: calc(anchor(--myAnchor 50%) + 5px);
bottom: anchor-size(width);

/* <percentage>s of the height of the containing block */
bottom: 10%;

/* Keyword value */
bottom: auto;

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

Values

<length>

A negative, null, or positive <length>:

<percentage>

A <percentage> of the containing block's height.

auto

Specifies that:

  • for absolutely positioned elements, the position of the element is based on the top property, while height: auto is treated as a height based on the content; or if top is also auto, the element is positioned where it should vertically be positioned if it were a static element.
  • for relatively positioned elements, the distance of the element from its normal position is based on the top property; or if top is also auto, the element is not moved vertically at all.
inherit

Specifies that the value is the same as the computed value from its parent element (which might not be its containing block). This computed value is then handled as if it were a <length>, <percentage>, or the auto keyword.

Formal definition

Initial valueauto
Applies topositioned elements
Inheritedno
Percentagesrefer to the height of the containing block
Computed valueif specified as a length, the corresponding absolute length; if specified as a percentage, the specified value; otherwise, auto
Animation typea length, percentage or calc();

Formal syntax

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

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

<anchor()> =
anchor( <anchor-name>? &&
<anchor-side> , <length-percentage>? )

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

<anchor-name> =
<dashed-ident>

<anchor-side> =
inside |
outside |
top |
left |
right |
bottom |
start |
end |
self-start |
self-end |
<percentage> |
center

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

Examples

Absolute and fixed positioning

This example demonstrates the difference in behavior of the bottom property, when position is absolute versus fixed.

HTML

html
<p>
  This<br />is<br />some<br />tall,<br />tall,<br />tall,<br />tall,<br />tall<br />content.
</p>
<div class="fixed"><p>Fixed</p></div>
<div class="absolute"><p>Absolute</p></div>

CSS

css
p {
  font-size: 30px;
  line-height: 2em;
}

div {
  width: 48%;
  text-align: center;
  background: rgb(55 55 55 / 20%);
  border: 1px solid blue;
}

.absolute {
  position: absolute;
  bottom: 0;
  left: 0;
}

.fixed {
  position: fixed;
  bottom: 0;
  right: 0;
}

Result

Specifications

Specification
CSS Positioned Layout Module Level 3
# insets

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
bottom
anchor()
Experimental
anchor-size()
Experimental
auto

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.

See also