Base Converter is the best free app to convert :

* Text
* Decimal
* Binary
* Octal
* Hexadecimal

Used for :
Convert text to decimal, text to binary, text to octal, text to hexa.
Convert decimal to binary, decimal to octal, decimal to hexa.
Convert binary to decimal, binary to octal, binary to hexa.
Convert octal to decimal, octal to binary, octal to hexa.
Convert hexa to decimal, hexa to binary, hexa to octal.

Note :
If you are converting from the text, it will convert each character of the text you enter, it means that if you convert back from e.g. hex to text then the result will not be the same as the text to hexa. Example: You enter text = duza, then the result of the conversion to hexa = 64757a61, but when you take into hexa = 64757a61 the results of the conversion to text = Èêô .