How to Understand Bits and Bytes on your Computer

1. Byte

   Unit of data
2. The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits.

 Base-2 System and the 8-bit Byte

1. The reason computers use the base-2 system is because it makes it a lot easier to implement them with current electronic technology. You could wire up and build computers that operate in base-10, but they would be fiendishly expensive right now. On the other hand, base-2 computers are relatively cheap.

   So computers use binary numbers, and therefore use binary digits in place of decimal digits. The word bitis a shortening of the words "Binary digIT." Whereas decimal digits have 10 possible values ranging from 0 to 9, bits have only two possible values: 0 and 1. Therefore, a binary number is composed of only 0s and 1s, like this: 1011. How do you figure out what the value of the binary number 1011 is? You do it in the same way we did it above for 6357, but you use a base of 2 instead of a base of 10. So:

   (1 * 2^3) + (0 * 2^2) + (1 * 2^1) + (1 * 2^0) = 8 + 0 + 2 + 1 = 11

   You can see that in binary numbers, each bit holds the value of increasing powers of 2. That makes counting in binary pretty easy. Starting at zero and going through 20, counting in decimal and binary looks like this:

    0 =     0
    1 =     1
    2 =    10
    3 =    11
    4 =   100
    5 =   101
    6 =   110
    7 =   111
    8 =  1000
    9 =  1001
   10 =  1010
   11 =  1011
   12 =  1100
   13 =  1101
   14 =  1110
   15 =  1111
   16 = 10000
   17 = 10001
   18 = 10010
   19 = 10011
   20 = 10100

2. 
   Bits are rarely seen alone in computers. They are almost always bundled together into 8-bit collections, and these collections are called bytes. Why are there 8 bits in a byte? A similar question is, "Why are there 12 eggs in a dozen?" The 8-bit byte is something that people settled on through trial and error over the past 50 years.
   
   With 8 bits in a byte, you can represent 256 values ranging from 0 to 255, as shown here:
     0 = 00000000
     1 = 00000001
     2 = 00000010
      ...
   254 = 11111110
   255 = 11111111