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

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Daniel Lemire

A computer science professor at the University of Quebec (TELUQ).

2 thoughts on “A megabyte is a mebibyte, and a kilobyte is a kibibyte”

  1. Not fair! I had that in my drafts for my blog – and now it’s like I’m going to copy you 🙂
    I guess I’ll have to translate it to french then. Oh, something completely different: I found the Canadian Semantic Web Interest Group and saw you maybe had a meeting planned in Montreal for September. That would land smack in the middle of the Semaine quĂ©bĂ©coise de l’informatique libre – http://semaine.facil.qc.ca/ , where standards are just as important as software. Maybe we could work on something together..?

  2. Copy away my friend.

    As for the SWIG meeting, the members have not yet spoken as to what type of meeting we’ll have so we don’t know.

    However, this week of free software is a fantastic idea.

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