Nibble meaning – what is it?

Computing tech­nolo­gies are con­stant­ly evolving and as the demand on systems increases, companies and users require ever greater ca­pac­i­ties for data storage and trans­mis­sion. Standard storage media have grown so much in capacity that in­for­ma­tion units such as the megabyte and gigabyte have become com­mon­place. When trans­mit­ting data, we encounter in­for­ma­tion such as Mbit/s which cor­re­sponds to a trans­mis­sion rate of 1,000,000 bits per second.

To un­der­stand the amount of data behind these terms, it is a good idea to get to know their smallest building blocks. While many users are already familiar with bits and bytes, the nibble is still fairly unknown. In the 1970s, the unit marked the beginning of faster data pro­cess­ing de­vel­op­ments. We introduce the nibble and its meaning and explain how con­vert­ing in­for­ma­tion between in­di­vid­ual units works.

A “nibble” (also “nybble” and “nyble” when referring to a “byte”) is the second smallest unit of in­for­ma­tion for data trans­mis­sion and storage. The term is a play on the word “bite” and alludes to being a fraction of a byte. More precisely, a nibble cor­re­sponds to half of a byte and thus four bits.

The nibble unit was developed in col­lab­o­ra­tion with the BCD code (Binary Coded Decimal), in which four bits each represent a digit between 0 and 9. These four bits cor­re­spond to one nibble. By putting multiple bits together, computers and proces­sors work faster. So-called 4-bit mi­cro­proces­sors were already in use at the beginning of the 1970s. Here, the amount of data that the processor processes in a single step consists of four bits or a nibble. This system laid the foun­da­tion for the de­vel­op­ment of more powerful proces­sors. Later, they were sum­ma­rized as 8, then 32 and finally 128 bits.

One bit is the smallest binary in­for­ma­tion unit and rep­re­sents the status 0 or 1. This measure cannot be further sub­di­vid­ed. There are many other units that represent multiples of a bit. One of the best-known rep­re­sen­ta­tives is the byte, which consists of eight bits. Since a bit can have two different states (0 and 1), there are some 28 pos­si­bil­i­ties for one byte. A byte cor­re­sponds to the smallest possible amount of data, making it an important measure to indicate memory size.

A nibble cor­re­sponds to exactly half of a byte and therefore consists of four bits. This also results in the al­ter­na­tive des­ig­na­tion “half-byte”. However, the nibble didn’t always consist of four bits. For example, Apple software first combined five and later six bits into a nibble. Nowadays, the term ex­clu­sive­ly refers to four bits. To make things fool-proof, some in the industry use un­mis­tak­able terms such as “semi-octet”, “quadbit” or “quartet”.

A nibble can have 16 (2⁴) different values from 0 to 15. In binary numbers, this cor­re­sponds to the values 0000 and 1111 and all their possible com­bi­na­tions. This unit of in­for­ma­tion is primarily used in mi­cro­con­trollers, com­mu­ni­ca­tion protocols, or assembly languages.

Nowadays, small units of in­for­ma­tion such as bit, nibble, and byte are no longer suitable to legibly represent the amount of data and storage ca­pac­i­ties. Therefore, different units exist to represent the multiples of a bit. The following table gives an overview of common data volumes and their con­ver­sion factors.

The term “nibble” emerged in 1958 through a joke remark by the late Professor David B. Benson. When speaking to a pro­gram­mer from the Los Alamos Sci­en­tif­ic Lab­o­ra­to­ry, Benson referred to “taking half a bite”. The professor re­mem­bered the statement when he named the rep­re­sen­ta­tion of a digit by four bits and thus in­tro­duced the nibble.