asin()

The asin() CSS function is a trigonometric function that returns the inverse sine of a number between -1 and 1. The function contains a single calculation that returns the number of radians representing an <angle>() between -90deg and 90deg.

Syntax

/* Single <number> values */
transform: rotate(asin(-0.2));
transform: rotate(asin(2 * 0.125));

/* Other values */
transform: rotate(asin(pi / 5));
transform: rotate(asin(e / 3));

Parameter

The asin(number) function accepts only one value as its parameter.

number: A calculation which resolves to a <number>() between -1 and 1.

Return value

The inverse sine of an number will always return an <angle>() between -90deg and 90deg.

If number is less than -1 or greater than 1, the result is NaN.
If number is 0⁻, the result is 0⁻.

Examples

Rotate elements

The asin() function can be used to rotate elements as it return an <angle>().

HTML

<div class="box box-1"></div>
<div class="box box-2"></div>
<div class="box box-3"></div>
<div class="box box-4"></div>
<div class="box box-5"></div>

CSS

body {
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 50px;
}

div.box {
  width: 100px;
  height: 100px;
  background: linear-gradient(orange, red);
}
div.box-1 {
  transform: rotate(asin(1));
}
div.box-2 {
  transform: rotate(asin(0.5));
}
div.box-3 {
  transform: rotate(asin(0));
}
div.box-4 {
  transform: rotate(asin(-0.5));
}
div.box-5 {
  transform: rotate(asin(-1));
}

css types asin()