Units of information: B represents byte

The idea

In computing, a byte is a group of 8 bits and is the standard unit for measuring storage and memory. The symbol for byte is an uppercase B, so 1 B means one byte. This is distinct from the lowercase b, which stands for bit. A common method is to read a capacity such as 500 MB as 500 megabytes, where the B confirms bytes rather than bits. Learners should recognise that the capitalisation carries meaning: B = byte, b = bit. When a question asks what B represents, the answer is byte, not bit, binary digit or baud. Being precise about this symbol prevents confusion when comparing storage sizes and data transfer rates, where bits and bytes are often both used.

What earns the marks

• B is the symbol for byte.
• A byte is a group of 8 bits.
• Lowercase b represents a bit, so capitalisation distinguishes byte from bit.
• A capacity written with B, such as MB or GB, is measured in bytes.

Common mistakes and how to put them right

• Confusing B with b.

  Put it right: The learner should state that uppercase B means byte and lowercase b means bit.

• Thinking B stands for bit.

  Put it right: Bit uses lowercase b.

• Assuming B means binary digit.

  Put it right: A binary digit is a bit, symbol b, while B is a byte.

Exam tips

• Read the capitalisation carefully: B and b are different units.
• Link B to byte and to 8 bits to justify your choice.
• Check the whole unit label, for example MB means megabytes, not megabits.