The amount of bits or characters in a word determines its length. The number of bits ranges from 4, 8, 12, 16, 32, and so on up to 64, implying that the word can be as long as 64 bits or as little as 8 bits. A byte is normally 8 bits long, which is shorter than a word. However, bytes are often treated as a unit for memory addressing reasons. Words must be at least 6 bits long if they are to be used as addresses.
A bit is the smallest unit of information. It can have two states: 0 or 1. Some computers store one bit per "cell"; others use several cells to represent one bit. Whether a bit is stored in a cell or not depends on the hardware technology used by the computer. For example, most microprocessors these days store bits in cells called registers. When a computer wants to transmit a single bit of data, it usually does so over a physical connection by setting or resetting some element such as a flip-flop or passing a current through a resistor. The receiving device reads this action and transforms it into a 0 or 1 depending on whether it is connected to a resister or not.
Words, bytes, and bits all refer to units of storage. The difference between words, bytes, and bits is their maximum length. A bit can only have two values. A word can be any length. A byte is always a power of 2.
A word is an ordered group of characters that the computer treats as a unit. The length of the word might be fixed or flexible. Words are the basic building blocks of computers. All data stored in memory consists of words.
A bit is a binary digit; it can be thought of as a variable that can take on one of two values: 0 or 1. Bits are the fundamental building block of all digital information. All data storage devices (discs, tapes, etc.) consist of many cells, where each cell can store one bit of data. Computers work with symbols called digits. These are just collections of bits. There are ten different digits used in computing: zero to nine. Each digit can have a value of 0 or 1. So a byte, or eight bits, represents one of these digits.
Words and bits are very similar. They both represent units of information. The only difference is that bits can take on more than two values, while words cannot. This means that bits are more versatile than words. For example, they can be used to represent tones instead of just on/off signals. However, words are useful for storing data because they can be combined together to form longer strings of information that can't be represented as combinations of bits.
A byte is 8 bits in length, and a word is the smallest unit of memory that can be addressed. A word's exact length varies. On Intel processors, a word is typically 32 or 64 bits.
Bytes and words are the same size on IBM PC compatible computers, but they are not always equal on other types of computers. For example, a byte is eight bits on IBM PS/2 computers, while it is seven bits wide on most Apple computers.
On PCs operating at 8-bit data rates (300 bps), each byte takes up one eighth of a bit period. At 9-bit data rates (450 bps), each byte takes up one ninth of a bit period. At 15-bit data rates (7500 bps), each byte takes up five one-thousandths of a bit period. At 16-bit data rates (8060 bps), each byte takes up three one-thousandths of a bit period.
At 24-bit data rates (1200 bps), each byte takes up one sixteenth of a bit period. At 32-bit data rates (1800 bps), each byte takes up one third of a bit period.