This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The mask-origin CSS property determines the origin of a mask.

/* Keyword values */
mask-origin: content-box;
mask-origin: padding-box;
mask-origin: border-box;
mask-origin: margin-box;
mask-origin: fill-box;
mask-origin: stroke-box;
mask-origin: view-box;

/* Multiple values */
mask-origin: padding-box, content-box;
mask-origin: view-box, fill-box, border-box;

/* Non-standard keyword values */
-webkit-mask-origin: content;
-webkit-mask-origin: padding;
-webkit-mask-origin: border;

/* Global values */
mask-origin: inherit;
mask-origin: initial;
mask-origin: unset;

For elements rendered as a single box, this property specifies the mask positioning area. In other words, this property specifies the origin position of an image specified by the mask-image CSS property. For elements rendered as multiple boxes, such as inline boxes on several lines or boxes on several pages, it specifies which boxes box-decoration-break operates upon to determine the mask positioning area.

Initial valueborder-box
Applies toall elements; In SVG, it applies to container elements excluding the <defs> element and all graphics elements
Computed valueas specified
Animation typediscrete
Canonical orderper grammar


One or more of the keyword values listed below, separated by commas.


The position is relative to the content box.
The position is relative to the padding box. For single boxes 0 0 is the upper left corner of the padding edge, 100% 100% is the lower right corner.
The position is relative to the border box.
The position is relative to the margin box.
The position is relative to the object bounding box.
The position is relative to the stroke bounding box.
Uses the nearest SVG viewport as reference box. If a viewBox attribute is specified for the element creating the SVG viewport, the reference box is positioned at the origin of the coordinate system established by the viewBox attribute and the dimension of the reference box is set to the width and height values of the viewBox attribute.
Same as content-box.
Same as padding-box.
Same as border-box.

Formal syntax


<geometry-box> = <shape-box> | fill-box | stroke-box | view-box

<shape-box> = <box> | margin-box

<box> = border-box | padding-box | content-box



#masked {
  width: 100px;
  height: 100px;
  margin: 10px;
  border: 10px solid blue;
  background-color: #8cffa0;
  padding: 10px;
  mask-image: url(;
  mask-origin: border-box; /* Can be changed in the live sample */


Specification Status Comment
CSS Masking Module Level 1
The definition of 'mask-origin' in that specification.
Candidate Recommendation Initial definition

Browser compatibility


FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support Yes -webkit- 1 ?53 ? Yes -webkit- 1 Yes -webkit- 1
fill-box No ? No No ? ?
stroke-box No ? No No ? ?
view-box No ? No No ? ?
Non-standard values content, padding, border1 -webkit- ? No No No4 -webkit-
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support ? ? ?53 ? ? ?
fill-box ? ? ? No ? ? No
stroke-box ? ? ? No ? ? No
view-box ? ? ? No ? ? No
Non-standard values content, padding, border2.1 -webkit- ? ? No ?3.2 -webkit- ?

1. The margin-box value is unsupported.


Document Tags and Contributors

Last updated by: fscholz,