How to convert Hexadecimal into Decimal

Hello, we are going to be looking at how to convert hex to decimal. This is going to be quite important in the CCNA, especially when working with subnetting and access control lists.

Hexadecimal is basically a base 16 number system (0 1 2 3 4 5 6 7 8 9 A B C D E F). Each of the hex positions corresponds to powers of 16.

So for example, BEEF in hex would be calculated as follows:

B    E    E    F
11   14   14   15   (decimal values)
×    ×    ×    ×    
16³  16²  16¹  16⁰  (powers of 16)
=    =    =    =
11×4096 + 14×256 + 14×16 + 15×1
= 45056 + 3584 + 224 + 15
= 48879

So BEEF in hex = 48879 in decimal.

Let's look at another example: FACE

F    A    C    E
15   10   12   14   (decimal values)
×    ×    ×    ×    
16³  16²  16¹  16⁰  (powers of 16)
=    =    =    =
15×4096 + 10×256 + 12×16 + 14×1
= 61440 + 2560 + 192 + 14
= 64206

So FACE in hex = 64206 in decimal.

The key thing to remember is that each position represents a power of 16, starting from 16⁰ on the right and increasing as you move left.