`sqrt()` CSS function

The sqrt() CSS function is an exponential function that returns the square root of a number.

The function pow(x, 0.5) is equivalent to sqrt(x).

Syntax

css

/* A <number> value */
width: calc(100px * sqrt(9)); /*  300px */
width: calc(100px * sqrt(25)); /*  500px */
width: calc(100px * sqrt(100)); /* 1000px */

Parameters

The sqrt(x) function accepts only one value as its parameter.

x: A calculation which resolves to a <number> greater than or equal to 0.

Return value

Returns a <number> which is the square root of x.

if x is +∞, the result is +∞.
If x is 0⁻, the result is 0⁻.
If x is less than 0, the result is NaN.

Formal syntax

<sqrt()> = 
  sqrt( <calc-sum> )  

<calc-sum> = 
  <calc-product> [ [ '+' | '-' ] <calc-product> ]*  

<calc-product> = 
  <calc-value> [ [ '*' | / ] <calc-value> ]*  

<calc-value> = 
  <number>        |
  <dimension>     |
  <percentage>    |
  <calc-keyword>  |
  ( <calc-sum> )  

<calc-keyword> = 
  e          |
  pi         |
  infinity   |
  -infinity  |
  NaN

Examples

undefined

Scale sizes based on square root

This example shows how you can use the sqrt() function to calculate sizes.

HTML

html

<div class="boxes">
  <div class="box">50px</div>
  <div class="box one">100px</div>
  <div class="box two">150px</div>
  <div class="box three">200px</div>
</div>

CSS

Here we are using CSS custom properties to define the sizes to be used. First, we declare the first size (--size-0), which is then used to calculate the other sizes.

--size-1 is calculated by multiplying the value of --size-0 (50px) by the square root of 4 (2), which results in 100px.
--size-2 is calculated by multiplying the value of --size-0 (50px) by the square root of 9 (3), which results in 150px.
--size-3 is calculated by multiplying the value of --size-0 (50px) by the square root of 16 (4), which results in 200px.

css

:root {
  --size-0: 50px;
  --size-1: calc(var(--size-0) * sqrt(4)); /*  100px */
  --size-2: calc(var(--size-0) * sqrt(9)); /*  150px */
  --size-3: calc(var(--size-0) * sqrt(16)); /*  200px */
}

.boxes {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
}

.box {
  width: var(--size-0);
  height: var(--size-0);
  background-color: tomato;
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
}

The sizes are then applied as the width and height values of the selectors.

css

.one {
  width: var(--size-1);
  height: var(--size-1);
}
.two {
  width: var(--size-2);
  height: var(--size-2);
}
.three {
  width: var(--size-3);
  height: var(--size-3);
}

Result

Specifications

CSS Values and Units Module Level 4

sqrt() CSS function