This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.


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

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 orderthe unique non-ambiguous order defined by the formal grammar


/* 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;


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


CSS Content

#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

Feature Chrome Firefox (Gecko) Internet Explorer Edge Opera Safari (WebKit)
Basic support (Yes)-webkit[1] 53.0 (53.0) No support ? (Yes)-webkit[1] (Yes)-webkit[1]
fill-box, stroke-box, view-box No support No support No support ? ? ?
content, padding, border 1.0-webkit No support No support ? No support 4.0-webkit
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support ? 53.0 (53.0) ? ? ?
fill-box, stroke-box, view-box ? No support ? ? ?
content, padding, border 2.1-webkit No support ? ? 3.2-webkit

[1] WebKit and Blink currently don't support the value margin-box.

Document Tags and Contributors

 Contributors to this page: DaveLand, chrisdavidmills, teoli, Sebastianz, rolfedh
 Last updated by: DaveLand,