PHP - log() Function

The PHP log() function is used to return the natural logarithm or logarithm to the specified base of a given number.

Syntax

log(number, base)

Parameters

`number`	`Required.` Specify the number.
`base`	`Optional.` Specify the base. Default is e

Return Value

Returns the natural logarithm or logarithm to the specified base of a given number.

Example:

In the below example, log() function is used to calculate the natural logarithm and logarithm to the specified base of a given number.

<?php
  $x = 10; 
  $y = 50;
  $z = 100;

  //calculate natural logarithm
  echo "log($x) equal to: ".log($x)."\n";
  echo "log($y) equal to: ".log($y)."\n";
  echo "log($z) equal to: ".log($z)."\n";

  echo "\n";
  //calculate base-10 logarithm 
  echo "log($x, 10) equal to: ".log($x, 10)."\n";
  echo "log($y, 10) equal to: ".log($y, 10)."\n";
  echo "log($z, 10) equal to: ".log($z, 10)."\n";

?>

The output of the above code will be:

log(10) equal to: 2.302585092994
log(50) equal to: 3.9120230054281
log(100) equal to: 4.6051701859881

log(10, 10) equal to: 1
log(50, 10) equal to: 1.698970004336
log(100, 10) equal to: 2

❮ PHP Math Functions