**Definition:**The hexadecimal number system (also called base-16) is a number system that uses 16 unique symbols to represent a particular value. Those symbols are 0-9 and A-F.

The number system that we use in daily life is called the decimal, or base-10, system and uses the symbols 0-9 to represent a value.

Many error messages and other various values used inside a computer are represented in the hexadecimal format.

For example, error codes called STOP codes, that display on a Blue Screen of Death, are always in hexadecimal format.

### How To Count in Hexadecimal

Counting in hexadecimal format is easy as long as you remember that there are 16 characters that make up each set of numbers.

In decimal format, we all know that we count like this:

0,1,2,3,4,5,6,7,8,9,10,11,12,13,... adding a 1 before beginning the set of 10 numbers over again (i.e. the number 10)

In hexadecimal format however, we count like this, including all 16 numbers:

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11,12,13... again, adding a 1 before beginning the 16 number set over.

Here are a few examples of some tricky hexadecimal "transitions" that you might find helpful:

...17, 18, 19, 1A, 1B...

...1E, 1F, 20, 21, 22...

...FD, FE, FF, 100, 101, 102...

**Also Known As:**hex, base-16

**Examples:**

*"Counting in hexadecimal can get a bit tricky sometimes but it's easy with a bit of practice."*