Bits and Bytes Guide to Data Units

Computer’s work on a system of ones and zeros called binary, a one or zero is called a bit, these numbers are combined into a sequence of eight to make a number range from 0 to 255 counted as 256. Eight bits is called a byte.

A bit is a single unit of one or zero, individually a bit means on or off or true and false. Data is stored as units called bytes, one byte is made of a combination of eight ones and zeros.

A byte is a combination of eight bits making a number range from 0 to 255 adding up to 256 combinations. All meaningful data is stored as bytes. A byte mostly contains information such as a letter or number, for example a byte could be the letter “A”.

A kilobyte is 1024 bytes, this means that a kilobyte is equal to about 1024 letters. A megabyte is 1024 kilobytes and so forth.

Binary and Decimal Units

Computer’s see information as ones and zeros, meaning a bit is base two and a byte is eight. In decimal units there are no bits as one decimal is one byte, a kilobyte is 1000 in decimal as so on.

Binary units:

Bit = 1
Bytes = 8
KiloBytes = 1024 Bytes
MegaBytes = 1024 KiloBytes
GigaBytes = 1024 MegaBytes
TeraBytes = 1024 GigaBytes
PetaBytes = 1024 TeraBytes

Decimal units:

byte = 1
kilobytes = 1000 bytes
megabytes = 1000 kilobytes
gigabytes = 1000 megabytes
terabytes = 1000 gigabytes
petabytes = 1000 terabytes

Abbreviations, an often confusing subject because there is more than one standard, it is recommended that everybody should footnote their units of measurement. The above units is mostly associated with storage and hard drive, thus is most commonly used. Also note the capitalization to distinguish the difference between binary and decimal.


Kb = Kilobits
Mb = Megabits

* Note this is often used interchangeably with binary and decimal.

Bits and Bytes

b = Bits
B = Bytes

* Note that is this is different with different standards, often bits is omitted.

Lower case bytes:

kb = 1000 bytes
mb = 1000 kilobytes

Upper case bytes:

KB = 1024 Bytes
MB = 1024 KiloBytes

Different Naming and Abbreviation Standards

Marketing for products or services use decimal units because it is often the largest number and is easier to understand. It is much easier to advertise a 1 Terabyte hard drive as 1 Terabyte decimal than to say 931 Gigabytes in binary.

Internet Speed and data transfer speed is often advertised as bits in decimal units, to convert bits to binary for the actual speed you will simply divide by 10 instead of 8. Example: 2.5 Megabits download is equal to 250 KiloBytes.

International Electrotechnical Commission (IEC) Standards


Byte (B) = 1 Byte
Kilobyte (KB) = 1000 Bytes
Megabyte (MB) = 1000 Kilobytes
Gigabyte (GB) = 1000 Megabytes
Terabyte (TB) = 1000 Gigabyte


Byte (B) = 8 Bits
Kibibyte (KiB) = 1024 Bytes
Mebibyte (MiB) = 1024 Kibibyte
Gibibyte (GiB) = 1024 Mebibyte
Tebibyte (TiB) = 1024 Gibibyte