Are you asking to convert from hex to decible, you count up to 16 using numbers and letters just like you could to number ten using numbers only.

Example

Decimal for 1st 16 values (up to 15)

0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15

Hex for the 1st 16values (up to 15)

0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f

Like decimal, hex uses can use more than one digit. example.

20 in decimal is simply that, 20. In hex it is 14. The 1 digit in 10 standing for the hex value of 16 plus the second digit 4 standing for 4. i.e. Hex works in powers of 16. Decimal in 10's and Binary in 2's.

To convert Decimal to binary, things go up in powers of 2's. 0001 is 4 bit binary for 1. 0010 is 2, 0011 is 3 and soforth. to convert from hex to binary, split the hex value into it's individual digits, and for each digit, work out the 4bit binary equivilent then add the 4bit blocks of binary together relative to the hex digits they were made from. example.

Hex value 3D1 in decimal is 977.

to convert to binary, 3 in hex is 3 in decimal so in 4 bit binary is 0011.

D in hex is 13 in decimal and is 1101 in binary.

1 in hex is 1 in decimal and is 0001 in binary.

add these 4 bit blocks together and you get 0011 1101 0001

Hence 3D1 hex = 001111010001 Binary.

Work it in reverse if needed.

You could just use Windows Calculator too.