The CSS align-items property sets the align-self value on all direct children as a group. The align-self property sets the alignment of an item within its containing block.

Currently this property is supported in Flexbox and CSS Grid Layout. In Flexbox it controls the alignment of items on the Cross Axis, in Grid Layout it controls the alignment of items on the Block Axis.

Syntax

/* Basic keywords */ 
align-items: normal; 
align-items: stretch; 

/* Positional alignment */ 
/* align-items does not take left and right values */
align-items: center; /* Pack items around the center */ 
align-items: start; /* Pack items from the start */ 
align-items: end; /* Pack items from the end */ 
align-items: flex-start; /* Pack flex items from the start */ 
align-items: flex-end; /* Pack flex items from the end */ 
align-items: self-start; 
align-items: self-end; 

/* Baseline alignment */
align-items: baseline; 
align-items: first baseline; 
align-items: last baseline; /* Overflow alignment (for positional alignment only) */ 
align-items: safe center; 
align-items: unsafe center; 

/* Global values */
align-items: inherit; 
align-items: initial; 
align-items: unset;

Values

normal
The effect of this keyword is dependent of the layout mode we are in:
  • In absolutely-positioned layouts, the keyword behaves like start on replaced absolutely-positioned boxes, and as stretch on all other absolutely-positioned boxes.
  • In static position of absolutely-positioned layouts, the keyword behaves as stretch.
  • For flex items, the keyword behaves as stretch.
  • For grid items, this keyword leads to a behavior similar to the one of stretch, except for boxes with an aspect ratio or an intrinsic sizes where it behaves like start.
  • The property doesn't apply to block-level boxes, and to table cells.
flex-start
The cross-start margin edges of the flex items are flushed with the cross-start edge of the line.
flex-end
The cross-end margin edges of the flex items are flushed with the cross-end edge of the line.
center
The flex items' margin boxes are centered within the line on the cross-axis. If the cross-size of an item is larger than the flex container, it will overflow equally in both directions.
start
The items are packed flush to each other toward the start edge of the alignment container in the appropriate axis.
end
The items are packed flush to each other toward the end edge of the alignment container in the appropriate axis.
self-start
The items are packed flush to the edge of the alignment container of the start side of the item, in the appropriate axis.
self-end
The items are packed flush to the edge of the alignment container of the end side of the item, in the appropriate axis.
baseline
first baseline
last baseline
All flex items are aligned such that their flex container baselines align. The item with the largest distance between its cross-start margin edge and its baseline is flushed with the cross-start edge of the line.
stretch
Flex items are stretched such that the cross-size of the item's margin box is the same as the line while respecting width and height constraints.
safe
Used alongside an alignment keyword. If the chosen keyword means that the item overflows the alignment container causing data loss, the item is instead aligned as if the alignment mode were start.
unsafe
Used alongside an alignment keyword. Regardless of the relative sizes of the item and alignment container and whether overflow which causes data loss might happen, the given alignment value is honored.

Formal syntax

normal | stretch | <baseline-position> | [ <overflow-position>? <self-position> ]

where
<baseline-position> = [ first | last ]? baseline
<overflow-position> = unsafe | safe
<self-position> = center | start | end | self-start | self-end | flex-start | flex-end

Example

CSS

#container {
  height:200px;
  width: 240px;
  align-items: center; /* Can be changed in the live sample */
  background-color: #8c8c8c;
}

.flex {
  display: flex;
  flex-wrap: wrap;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, 50px);
}

div > div {
  box-sizing: border-box;
  border: 2px solid #8c8c8c;
  width: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
}

#item1 {
  background-color: #8cffa0;
  min-height: 30px;
}

#item2 {
  background-color: #a0c8ff;
  min-height: 50px;
}

#item3 {
  background-color: #ffa08c;
  min-height: 40px;
}

#item4 {
  background-color: #ffff8c;
  min-height: 60px;
}

#item5 {
  background-color: #ff8cff;
  min-height: 70px;
}

#item6 {
  background-color: #8cffff;
  min-height: 50px;
  font-size: 30px;
}

select {
  font-size: 16px;
}

.row {
  margin-top: 10px;
}

HTML

<div id="container" class="flex">
  <div id="item1">1</div>
  <div id="item2">2</div>
  <div id="item3">3</div>
  <div id="item4">4</div>
  <div id="item5">5</div>
  <div id="item6">6</div>
</div>

<div class="row">
  <label for="display">display: </label>
  <select id="display">
    <option value="flex">flex</option>
    <option value="grid">grid</option>
  </select>
</div>

<div class="row">
  <label for="values">align-items: </label>
  <select id="values">
    <option value="normal">normal</option>
    <option value="flex-start">flex-start</option>
    <option value="flex-end">flex-end</option>
    <option value="center" selected>center</option>
    <option value="baseline">baseline</option>
    <option value="stretch">stretch</option>

    <option value="start">start</option>
    <option value="end">end</option>
    <option value="self-start">self-start</option>
    <option value="self-end">self-end</option>
    <option value="left">left</option>
    <option value="right">right</option>

    <option value="first baseline">first baseline</option>
    <option value="last baseline">last baseline</option>

    <option value="safe center">safe center</option>
    <option value="unsafe center">unsafe center</option>
    <option value="safe right">safe right</option>
    <option value="unsafe right">unsafe right</option>
    <option value="safe end">safe end</option>
    <option value="unsafe end">unsafe end</option>
    <option value="safe self-end">safe self-end</option>
    <option value="unsafe self-end">unsafe self-end</option>
    <option value="safe flex-end">safe flex-end</option>
    <option value="unsafe flex-end">unsafe flex-end</option>
  </select>
</div>

Result

Specifications

Specification Status Comment
CSS Box Alignment Module Level 3
The definition of 'align-items' in that specification.
Working Draft Update to latest syntax definitions.
CSS Flexible Box Layout Module
The definition of 'align-items' in that specification.
Candidate Recommendation Initial definition

Initial valuenormal
Applies toall elements
Inheritedno
Mediavisual
Computed valueas specified
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Browser compatibility

Support in Flex layout

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support

52

291

21 -webkit-

12

12 -webkit-

202

49 -webkit-

18 —?3

48 -webkit- 4

11512.17 -webkit-
first baseline and last baseline ? ?45 ? ? ?
start and end ? ?45 ? ? ?
left and right ? ?45 ? ? ?
safe and unsafe No No63 No No ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support

52

291

21 -webkit-

52

291

25 -webkit-

Yes

Yes -webkit-

202

49 -webkit-

18 —?3

48 -webkit- 4

12.17 -webkit- ?
first baseline and last baseline ? ? ?45 ? ? ?
start and end ? ? ?45 ? ? ?
left and right ? ? ?45 ? ? ?
safe and unsafe ? ? No63 ? ? No

1. Older versions of the specification treat absolute positioned children as though they are a 0 by 0 flex item. Later specification versions take the children out of the flow and set their positions based on align and justify properties. Chrome implements the new behavior beginning with Chrome 52.

2. Multi-line flexbox has been supported since Firefox 28.

3. From version 18: this feature is behind the layout.css.flexbox.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

4. From version 48: this feature is behind the layout.css.prefixes.webkit preference (needs to be set to true). To change preferences in Firefox, visit about:config.

5. In Internet Explorer 10 and 11, if column flex items have align-items: center; set on them and their content is too large, then they will overflow the bounds of their container. See Flexbug #2.

Support in Grid layout

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support571652 ?4410.1
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support5752 Yes524410.36.2

See also