PHP sqrt() Function

The PHP sqrt() function returns the square root of the given number. In special cases it returns the following:

If the argument is NAN or less than zero, then the result is NAN.
If the argument is positive infinity, then the result is positive infinity.

Syntax

sqrt(number)

Parameters

number Required. Specify a number.

Return Value

Returns the square root of the specified number (returns NAN for negative number).

Example:

In the example below, sqrt() function is used to find out the square root of the given number.

<?php
echo "sqrt(4) = ".sqrt(4)."\n";
echo "sqrt(25) = ".sqrt(25)."\n";
echo "sqrt(50) = ".sqrt(50)."\n";
echo "sqrt(-50) = ".sqrt(-50)."\n";
echo "sqrt(INF) = ".sqrt(INF)."\n";
echo "sqrt(-INF) = ".sqrt(-INF)."\n";
echo "sqrt(NAN) = ".sqrt(NAN)."\n";
?>

The output of the above code will be:

sqrt(4) = 2
sqrt(25) = 5
sqrt(50) = 7.0710678118655
sqrt(-50) = NAN
sqrt(INF) = INF
sqrt(-INF) = NAN
sqrt(NAN) = NAN

❮ PHP Math Reference