sin()

The sin() CSS function is a trigonometric function that returns the sine of a number, which is a value between -1 and 1. The function contains a single calculation that must resolve to either a {{cssxref("<number>")}} or an {{cssxref("angle")}} by interpreting the result of the argument as radians. That is, sin(45deg), sin(0.125turn), and sin(3.14159 / 4) all represent the same value, approximately 0.707.

css

transform: translateX(calc(cos(0deg) * 140px))
  translateY(calc(sin(0deg) * -140px));

css

transform: translateX(calc(cos(90deg) * 140px))
  translateY(calc(sin(90deg) * -140px));

css

transform: translateX(calc(cos(135deg) * 140px))
  translateY(calc(sin(135deg) * -140px));

css

transform: translateX(calc(cos(180deg) * 140px))
  translateY(calc(sin(180deg) * -140px));

css

transform: translateX(calc(cos(-45deg) * 140px))
  translateY(calc(sin(-45deg) * -140px));

html

<div class="circle">
  <span class="dot" id="example-element"></span>
</div>

css

:root {
  --radius: 140px;
  --dot-size: 10px;
}
.circle {
  display: grid;
  place-content: center;
  margin: 0 auto;
  width: calc(var(--radius) * 2);
  aspect-ratio: 1;
  border-radius: 50%;
  border: 2px solid #666666;
  background-image:
    radial-gradient(black var(--dot-size), transparent var(--dot-size)),
    linear-gradient(135deg, blue, deepskyblue, lightgreen, lavender, honeydew);
}
.dot {
  display: block;
  width: var(--dot-size);
  aspect-ratio: 1;
  border-radius: 50%;
  border: 2px solid #666666;
  background-color: #ff6666;
  transform: translateX(calc(cos(0deg) * var(--radius)))
    translateY(calc(sin(0deg) * var(--radius) * -1));
}

Syntax

css

/* Single <angle> values */
width: calc(100px * sin(45deg));
width: calc(100px * sin(0.25turn));
width: calc(100px * sin(1.0471967rad));

/* Single <number> values */
width: calc(100px * sin(63.673));
width: calc(100px * sin(2 * 0.125));

/* Other values */
width: calc(100px * sin(pi / 2));
width: calc(100px * sin(e / 4));

Parameters

The sin(angle) function accepts only one value as its parameter.

angle
- : A calculation which resolves to a {{cssxref("<number>")}} or an {{cssxref("angle")}}. When specifying unitless numbers they are interpreted as a number of radians, representing an {{cssxref("angle")}}

Return value

The sine of an angle will always return a number between −1 and 1.

If angle is infinity, -infinity, or NaN, the result is NaN.
If angle is 0⁻, the result is 0⁻.

Formal syntax

Examples

Changing box sizes

In this example, sin(30deg) will return 0.5, making the box have a 50px width and a 50px height.

css

div {
  background-color: red;
  width: calc(sin(30deg) * 100px);
  height: calc(sin(30deg) * 100px);
}

Controlling animation duration

Another use case is to control the {{cssxref("animation-duration")}}, reducing the duration based on the sine value. In this case, the animation duration will be 1s.

css

div {
  animation-name: myAnimation;
  animation-duration: calc(sin(0.25turn) * 1s);
}