css types transform-function scale()

The scale() CSS function defines a transformation that resizes an element on the 2D plane. Because the amount of scaling is defined by a vector, it can resize the horizontal and vertical dimensions at different scales. Its result is a <transform-function>() data type.

This scaling transformation is characterized by a two-dimensional vector. Its coordinates define how much scaling is done in each direction. If both coordinates are equal, the scaling is uniform (isotropic) and the aspect ratio of the element is preserved (this is a homothetic transformation).

When a coordinate value is outside the [-1, 1] range, the element grows along that dimension; when inside, it shrinks. A negative value results in a point reflection in that dimension. The value 1 has no effect.

Note: The scale() function only scales in 2D. To scale in 3D, use scale3d() instead.

Syntax

The scale() function is specified with either one or two values, which represent the amount of scaling to be applied in each direction. 

scale(sx)

scale(sx, sy)

Values

sx

A <number>() or <percentage>() representing the abscissa of the scaling vector.

sy

A <number>() or <percentage>() representing the ordinate of the scaling vector. If not defined, its default value is sx, resulting in a uniform scaling that preserves the element's aspect ratio.

Cartesian coordinates on ℝ^2 Homogeneous coordinates on ℝℙ^2 Cartesian coordinates on ℝ^3 Homogeneous coordinates on ℝℙ^3
( sx 0 0 sy ) ( sx 0 0 0 sy 0 0 0 1 ) ( sx 0 0 0 sy 0 0 0 1 ) ( sx 0 0 0 0 sy 0 0 0 0 1 0 0 0 0 1 )
[sx 0 0 sy 0 0]

Accessibility concerns

Scaling/zooming animations are problematic for accessibility, as they are a common trigger for certain types of migraine. If you need to include such animations on your website, you should provide a control to allow users to turn off animations, preferably site-wide.

Also, consider making use of the prefers-reduced-motion media feature — use it to write a media query that will turn off animations if the user has reduced animation specified in their system preferences.

Find out more:

Examples

Scaling the X and Y dimensions together

HTML

<div>Normal</div>
<div class="scaled">Scaled</div>

CSS

div {
  width: 80px;
  height: 80px;
  background-color: skyblue;
}

.scaled {
  transform: scale(0.7); /* Equal to scaleX(0.7) scaleY(0.7) */
  background-color: pink;
}

Scaling X and Y dimensions separately, and translating the origin

HTML

<div>Normal</div>
<div class="scaled">Scaled</div>

CSS

div {
  width: 80px;
  height: 80px;
  background-color: skyblue;
}

.scaled {
  transform: scale(2, 0.5); /* Equal to scaleX(2) scaleY(0.5) */
  transform-origin: left;
  background-color: pink;
}

See also