What is the Difference Between a Bit and a Byte?

A bit, short for binary digit, is the smallest unit of measurement used for information storage in computers. A bit is represented by a 1 or a 0 with a value of true or false, sometimes expressed as on or off. Eight bits form a single byte of information, also known as an octet. Thus, the difference between a bit and a byte is size, or the amount of information stored.

For example, it takes eight bits (1 byte) to store a single character. The capital letter “A” is expressed digitally as 01000001. A small case “a” is represented in binary code as 01100001. Notice the third bit is different in each octet. By rearranging the bits within the octet, a byte is capable of producing 256 unique combinations to form letters, numbers, special characters and symbols.

It can get confusing keeping units of storage straight, but if you have trouble remembering which is a bit and a byte, note that the smaller word is the smaller unit of storage. Once the difference between a bit and a byte is understood, this helps to remember the difference between greater units such as the kilobit and kilobyte.

A kilobit is 1000 bits, though in the binary system it is designated as 1024 bits due to the amount of space required to store a kilobit using common operating systems and storage schemes. For simplicity, however, you can think of kilo as referring to 1000 to more easily remember what a kilobit is. A kilobyte then, would be 1000 bytes.

Knowing the difference between a bit and a byte helps to understand megabits, megabytes, gigabits and gigabytes. For example, 1000 kilobits is 1 megabit, and 1000 kilobytes is 1 megabyte. Since we know a bit is 8x smaller than a byte, we know that one megabyte is 8x larger than 1 megabit. Following this pattern, 1000 megabits is 1 gigabit, and 1000 megabytes 1 gigabyte.

Internet connection speeds are expressed in terms of data transfer rates in both directions (uploading and downloading), as bits or bytes per second. Abbreviations are unfortunately not standardized, making it easy for customers or potential clients to confuse a bit and a byte when trying to determine bang for the buck. For example, a speed of “750 kbps” might be misinterpreted by a customer as meaning 750 kilobytes per second – or 8x faster than what the provider means.

A rule of thumb generally reliable is that small case abbreviations typically refer to bits, while a capital letter typically refers to bytes. Hence kilobits per second would be “kbps” and kilobytes would be “KBps,” or “kBps.” The same holds for megabits (mbps), and megabytes per second (MBps). Bits might also be expressed as “Kbit,” “Mbit,” or “Gbit.”