align-items

The CSS align-items property defines how the browser distributes space between and around flex items along the cross-axis of their container. This means it works like justify-content but in the perpendicular direction.

/* Basic keywords */ 
align-items: normal; 
align-items: stretch; 
/* Positional alignment */ 
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; 
align-items: left; /* Pack items from the left */ 
align-items: right; /* Pack items from the right */ 
/* 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;

The difference to the align-content property is that it specifies the alignment of the items within the current flex container's line, whereas align-content specifies the alignment of the lines themselves.

Syntax

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 edge of the flex item is flushed with the cross-start edge of the line.

flex-end

The cross-end margin edge of the flex item is flushed with the cross-end edge of the line.

center

The flex item's margin box is centered within the line on the cross-axis. If the cross-size of the item is larger than the flex container, it will overflow equally in both directions.

start

The item is packed flush to each other toward the start edge of the alignment container in the appropriate axis.

end

The item is packed flush to each other toward the end edge of the alignment container in the appropriate axis.

center

The items are packed flush to each other toward the center of the of the alignment container.

left

The items are packed flush to each other toward the left edge of the alignment container. If the property’s axis is not parallel with the inline axis, this value behaves like start.

right

The items are packed flush to each other toward the right edge of the alignment container in the appropriate axis. If the property’s axis is not parallel with the inline axis, this value behaves like start.

self-start

The items is packed flush to the edge of the alignment container of the start side of the item, in the appropriate axis.

self-end

The item is 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 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 as the cross-size of the item's margin box is the same as the line while respecting width and height constraints.

safe

If the size of the item overflows the alignment container, the item is instead aligned as if the alignment mode were start.

unsafe

Regardless of the relative sizes of the item and alignment container, the given alignment value is honored.

Formal syntax

flex-start | flex-end | center | baseline | stretch

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>

var values = document.getElementById('values');
var display = document.getElementById('display');
var container = document.getElementById('container');
values.addEventListener('change', function (evt) {
  container.style.alignItems = evt.target.value;
});
display.addEventListener('change', function (evt) {
  container.className = evt.target.value;
});

Result

Specifications

Browser compatibility

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

[2] To activate flexbox support in Firefox 18 and 19, the user has to visit about:config and change the value of the layout.css.flexbox.enabled preference to true. Multi-line flexbox has been supported since Firefox 28.

In addition to the unprefixed support, Gecko 48.0 (Firefox 48.0 / Thunderbird 48.0 / SeaMonkey 2.45) added support for a -webkit prefixed version of the property for web compatibility reasons behind the preference layout.css.prefixes.webkit, defaulting to false. Since Gecko 49.0 (Firefox 49.0 / Thunderbird 49.0 / SeaMonkey 2.46) the preference defaults to true.

[3] In Internet Explorer 10-11 (but not 12+), if column flex items have align-items: center; set on them and their content is too large, they will overflow the bounds of their container. See Flexbug #2 for more info.

See also

• Using CSS flexible boxes