PHP Function Reference

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