kilobyte

IPA/ˈkɪləbaɪt/
KK[kˈɪlobˌaɪt]IPA/ˈkɪləbaɪt/

kilobyte — noun

  • kilobytesingular
  • kilobytesplural

1. a standard measure of digital information that equals 1,024 bytes, commonly used

1.nounB1
Definition

a standard measure of digital information that equals 1,024 bytes, commonly used to describe computer memory capacity or the size of files

Example

The email Yuki sent was only two kilobytes in size.

collocation: [number] kilobytes in size

Each character in a plain text file takes up about one kilobyte of storage space.

collocation: kilobyte of [storage/memory/data]

Common collocations
  • kilobytes of memory
  • kilobytes of RAM
  • kilobytes of storage
  • file size in kilobytes
Synonyms
  • kibibyte

    the precise IEC term for 1,024 bytes; less common in casual usage but preferred in technical documentation

  • unit of memory

    a more general phrase describing what a kilobyte measures

Usage Note

Commonly abbreviated as KB (with capital K). This definition is standard when talking about computer memory (RAM, ROM) and traditional file-size measurements. The term 'kibibyte' (KiB) was introduced by the IEC in 1998 as the exact name for 1,024 bytes, but 'kilobyte' remains far more common in everyday computing.

Common Mistakes

The flash drive holds 64 kilobytes, which is exactly 64,000 bytes.
The flash drive holds 64 kilobytes, which is 65,536 bytes (64 × 1,024).
In computer memory contexts, 1 kilobyte equals 1,024 bytes, not 1,000.
Download speeds are measured in KB/s, meaning 1,000 bytes per second.
Download speeds are measured in KB/s, and each KB is 1,024 bytes.
The binary definition is standard in operating system displays.

2. a decimal measure of digital information that equals 1,000 bytes, consistent wit

2.nounB2
Definition

a decimal measure of digital information that equals 1,000 bytes, consistent with the International System of Units (SI); used mainly by storage device makers and in data transfer speed specifications

Example

Hard drive manufacturers often measure a kilobyte as 1,000 bytes rather than 1,024.

contrast: decimal (1,000) vs binary (1,024)

The network transfer rate was shown as 50 kilobytes per second using the decimal system.

context: data transfer rate

Common collocations
  • decimal kilobyte
  • per second (kB/s)
  • advertised in kilobytes
Synonyms
  • kB

    the SI abbreviation with lowercase k, used to distinguish the decimal definition

Usage Note

Often abbreviated as kB (lowercase k). This definition follows the SI metric system and is common in hard drive, solid-state drive, and network speed specifications. Operating systems typically report sizes using the binary definition (1,024 bytes), which can cause confusion when the advertised capacity differs from what the computer displays.

Common Mistakes

My 256 kB SSD is exactly 262,144 bytes.
My 256 kB SSD is exactly 256,000 bytes when the decimal definition is used.
Storage manufacturers use 1 kB = 1,000 bytes; check whether the source is decimal or binary.

Word family

Synonym discussion

Sense: noun/1

A kilobyte (KB, 1,024 bytes) and a kibibyte (KiB, also 1,024 bytes) refer to the same quantity, but 'kibibyte' is the precise IEC-standard term meant to eliminate confusion with the decimal 'kilobyte' (1,000 bytes). In practice, most operating systems and casual users still say 'kilobyte' when they mean 1,024 bytes. A megabyte (MB) is roughly 1,000 times larger — 1,024 KB. For everyday file sizes (text documents, small images), KB and KiB are appropriate; once files reach music or photo size, MB becomes the natural unit.

kilobyte ↗kibibyte ↗megabyte ↗

Common collocations

Nouns

Phrases

  • measured in kilobytes
  • size in kilobytes
  • measured in kilobytes

Prepositions

  • in kilobytes
  • kilobytes of

Etymology

GreekEnglish

Formed by combining the Greek prefix 'kilo-' (meaning 'thousand') with the English word 'byte' (a unit of digital information coined in the 1950s from 'bite', respelled to avoid confusion with 'bit'). The binary interpretation (1,024) arose because computer memory naturally uses powers of two, making 2¹⁰ the practical value — close enough to the prefix's 'thousand' meaning to share the name. The International Electrotechnical Commission introduced 'kibibyte' in 1998 to resolve the resulting ambiguity.