files/en-us/web/css/reference/values/atan2/index.md
The atan2() CSS function is a trigonometric function that returns the inverse tangent of two values between -infinity and infinity. The function accepts two arguments and returns an {{cssxref("angle")}} between -180deg and 180deg, without implying any specific unit such as radians.
/* Two <number> values */
transform: rotate(atan2(3, 2));
/* Two <dimension> values */
transform: rotate(atan2(1rem, -0.5rem));
/* Two <percentage> values */
transform: rotate(atan2(20%, -30%));
/* Other values */
transform: rotate(atan2(pi, 45));
transform: rotate(atan2(e, 30));
The atan2(y, x) function accepts two comma-separated values as its parameters. Each value can be a {{cssxref("<number>")}}, a {{cssxref("<dimension>")}}, or a {{cssxref("<percentage>")}}. Both values must be of the same type, although if they are {{cssxref("<dimension>")}} they can be of different units (example: atan2(100px, 5vw) is valid).
y
x
Given two values x and y, the function atan2(y, x) calculates and returns the {{cssxref("angle")}} between the positive x-axis and the ray from the origin to the point (x, y).
{{CSSSyntax}}
The atan2() function can be used to {{cssxref("transform-function/rotate", "rotate")}} elements as it return an {{cssxref("angle")}} .
<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>
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(atan2(3, 2));
}
div.box-2 {
transform: rotate(atan2(3%, -2%));
}
div.box-3 {
transform: rotate(atan2(-1, 0.5));
}
div.box-4 {
transform: rotate(atan2(1, 0.5));
}
div.box-5 {
transform: rotate(atan2(1rem, -0.5rem));
}
{{EmbedLiveSample('Rotate elements', '100%', '200px')}}
{{Specifications}}
{{Compat}}