PHP base_convert( ) Math Function

The base_convert() function in PHP is used to convert a number given in an arbitrary base to a desired base. 
Both the base should be between 2 and 32 and bases with digits greater than 10 are represented with letters a-z i.e 10 is represented as a, 11 is represented as b and 35 is represented as z. 
The case of the letters is not sensitive.

Syntax:

string base_convert($inpNumber, $fromBase, $desBase)

Parameters Used: This function accepts three parameters and are described below: 

1. $inpNumber : It is the number to be converted.
2. $fromBase : It is the original base of the number.
3. $desBase : It is the base to which you want to convert.

Return Value: It returns a string that represents the number converted to the desired base.

Examples: 

Input : base_convert(B296, 16, 8)
Output : 131226

Input : base_convert(B296, 16, 2)
Output : 1011001010010110

Input : base_convert(621, 8, 16)
Output : 191

Input : base_convert(110011, 2, 16)
Output : 33

Below programs illustrate the base_convert() function in PHP: 

• Converting hexadecimal to octal:

PHP

<?php

$hexadec = "B296";
echo base_convert($hexadec, 16, 8);

?>

Output: 

131226

• Converting hexadecimal to binary:

PHP

<?php

$hexadec = "B296";
echo base_convert($hexadec, 16, 2);

?>

Output: 

1011001010010110

• Converting octal to hexadecimal:

PHP

<?php

$octal = "621";
echo base_convert($octal, 8, 16);

?>

Output: 

191

• Converting binary to hexadecimal:

PHP

<?php

$binary = "110011";
echo base_convert($binary, 2, 16);

?>

Output: 

33

Reference: 
http://php.net/manual/en/function.base-convert.php