Computer data and file size is normally measured in binary code using the binary number system (counted by factors of two 1, 2, 4, 8, 16, 32, 64, etc), the prefixes for the multiples are based on the metric system! The nearest binary number to 1,000 is 2^10 or 1,024; thus 1,024 bytes was named a Kilobyte. So, although a metric “kilo” equals 1,000 (e.g. one kilogram = 1,000 grams), a binary “Kilo” equals 1,024 (e.g. one Kilobyte = 1,024 bytes).

bit | byte | Kilobyte | Megabyte | Gigabyte | |

bit | 1 | 8 | 8,192 | 8,388,608 | 8,589,934,592 |

byte | 8 | 1 | 1,024 | 1,048,576 | 1,073,741,824 |

Kilobyte | 8,192 | 1,024 | 1 | 1,024 | 1,048,576 |

Megabyt | 8,388,608 | 1,048,576 | 1,024 | 1 | 1,024 |

Gigabyte | 8,589,934,592 | 1,073,741,824 | 1,048,576 | 1,024 | 1 |

Terabyte | 8,796,093,022,208 | 1,099,511,627,776 | 1,073,741,824 | 1,048,576 | 1,024 |

Petabyte | 9,007,199,254,740,990 | 1,125,899,906,842,620 | 1,099,511,627,776 | 1,073,741,824 | 1,048,576 |

Exabyte | 9,223,372,036,854,770,000 | 1,152,921,504,606,840,000 | 1,125,899,906,842,620 | 1,099,511,627,776 | 1,073,741,824 |

Zettabyt | 9,444,732,965,739,290,000,000 | 1,180,591,620,717,410,000,000 | 1,152,921,504,606,840,000 | 1,125,899,906,842,620 | 1,099,511,627,776 |