This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Warning: This is a property of the original CSS Flexible Box Layout Module draft, and has been replaced by a newer standard.

The box-align CSS property specifies how an element aligns its contents across its layout in a perpendicular direction. The effect of the property is only visible if there is extra space in the box.

See flexbox for information about the current standard.

/* Keyword values */
box-align: start;
box-align: center;
box-align: end;
box-align: baseline;
box-align: stretch;

/* Global values */
box-lines: inherit;
box-lines: initial;
box-lines: unset;

The direction of layout depends on the element's orientation: horizontal or vertical.

Initial valuestretch
Applies toelements with a CSS display value of box or inline-box
Computed valueas specified
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar


The box-align property is specified as one of the keyword values listed below.


The box aligns contents at the start, leaving any extra space at the end.
The box aligns contents in the center, dividing any extra space equally between the start and the end.
The box aligns contents at the end, leaving any extra space at the start.
The box aligns the baselines of the contents (lining up the text). This only applies if the box's orientation is horizontal.
The box stretches the contents so that there is no extra space in the box.

Formal syntax

start | center | end | baseline | stretch


<!DOCTYPE html>
<title>CSS box-align example</title>
div.example {
  display: box;                   /* As specified */
  display: -moz-box;              /* Mozilla */
  display: -webkit-box;           /* WebKit */
  /* Make this box taller than the children, 
     so there is room for the box-pack */
  height: 400px;           
  /* Make this box wider than the children
     so there is room for the box-align */
  width: 300px;

  /* Children should be oriented vertically */
  box-orient: vertical;           /* As specified */
  -moz-box-orient: vertical;      /* Mozilla */
  -webkit-box-orient: vertical;   /* WebKit */

  /* Align children to the horizontal center of this box */
  box-align: center;              /* As specified */
  -moz-box-align: center;         /* Mozilla */
  -webkit-box-align: center;      /* WebKit */
  /* Pack children to the bottom of this box */
  box-pack: end;                  /* As specified */
  -moz-box-pack: end;             /* Mozilla */
  -webkit-box-pack: end;          /* WebKit */

div.example > p {            
  /* Make children narrower than their parent, 
     so there is room for the box-align */ 
  width: 200px;
  <div class="example">
    <p>I will be second from the bottom of div.example, centered horizontally.</p>
    <p>I will be on the bottom of div.example, centered horizontally.</p>


The edge of the box designated the start for alignment purposes depends on the box's orientation:

Horizontal top
Vertical left

The edge opposite to the start is designated the end.

If the alignment is set using the element's align attribute, then the style is ignored.


Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes -webkit- Yes -webkit-

49 -webkit-

48 -webkit- 1

Yes -moz-

No Yes -webkit-

3 -webkit-

1.1 —? -khtml-

FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes -webkit- Yes -webkit- Yes -webkit- No Yes -webkit- ? ?

1. 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.

See also