The "base_convert()" function converts a number between arbitrary bases.

    base_convert(number,frombase,tobase)

In the above syntax "number" is the orginal value, "frombase" is the original base of number, "tobase" the base to convert to.

   <?php
   $hex = 'A37334';
   echo base_convert($hex,16,2);
   ?>

    101000110111001100110100

In the above example the hexa decimal number "A37334" is converted to binary number as the "frombase" value is "16", "tobase" value is "2".