A kilobyte can mean two slightly different things, depending on context:

  • In most computing contexts (RAM, traditional CS teaching), 1 kilobyte = 1,024 bytes (that is 2102^{10}210 bytes).
  • In strict SI/decimal usage (some storage devices, standards), 1 kilobyte = 1,000 bytes , while 1 kibibyte (KiB) = 1,024 bytes.

For everyday programming and tech discussions, people almost always mean 1,024 bytes when they say “kilobyte.”