Daniel Lemire's blog

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Daniel Lemire is a computer science professor at the Data Science Laboratory of the Université du Québec (TÉLUQ) in Montreal. His research is focused on software performance and data engineering. He is a techno-optimist and a free-speech advocate.

27th July 2004, 1 min read

A megabyte is a mebibyte, and a kilobyte is a kibibyte

If you’ve been annoyed about the fact that a kilobyte has 1024 bytes and not 1000 bytes, well, you were right all along! What people call a kilobyte is really a kibibyte. (Thanks to Owen for pointing it out to me!)

Examples and comparisons with SI prefixes | one kibibit | 1 Kibit = 2¹⁰ bit = 1024 bit | one kilobit | 1 kbit = 10³ bit = 1000 bit | one mebibyte | 1 MiB = 2²⁰ B = 1 048 576 B | one megabyte | 1 MB = 10⁶ B = 1 000 000 B | one gibibyte | 1 GiB = 2³⁰ B = 1 073 741 824B | one gigabyte | 1 GB = 10⁹ B = 1 000 000 000 B |

Source: Definitions of the SI units: The binary prefixes