# bit into kilobits & megabits

Discussion in 'General Electronics Chat' started by aamirali, Aug 19, 2013.

1. ### aamirali Thread Starter Member

Feb 2, 2012
415
2
I saw that 1kilobits = 1024 bits & so on.

but many times I saw people use 1 kilobits = 1000 bits . why is that so .

but normally this is not a problem with bytes,kilobytes .....

1kB = 1024 bytes.

2. ### WBahn Moderator

Mar 31, 2012
20,245
5,758
The problem is the same whether you are talking bits or bytes.

The basic problem is that when people first started throwing around prefixes for the number of bits and bytes, the only people talking or listening were pretty much techie types. For most purposes, bits and bytes break out into powers of two. Since 2^10 = 1024 and this is close to 1000, they adopted (co-opted, actually) the use of the k prefix to mean a multiple of 2^10. Later, as things got larger in scale, they adopted M to mean a multiple of 2^20 = 1048576. Since the conversations were almost exclusively among people "in the know", this caused little problem. If things had stayed this way, we probably would have been okay as the rules would have been nice and consistent -- when talking about bits and bytes, k and M mean 2^10 and 2^20 and then the same for G, T, and so forth.

But things didn't stay the same. Digital went mainstream and now you have tons of people who don't know diddley about binary (and don't want to) and they think only in terms of power of ten. Worse, you have marketers who can leverage the difference to make their stuff appear more attractive. Instead of advertising a 1GB drive meaning 2^30, they advertise a 1.07GB drive, making you think you're getting 70MB more.

But it gets worse.

Although I think they cleaned this up in Win7, in older Windows OS they would list file sizes as so many KB or so many MB, and KB was 1024 bytes, but MB was 1000x1024 bytes.

The "official" solution is to use a new (well, not that new, now) set of prefixes for binary quantities. The first few of these are the Kibi, the Mebi, and the Gibi, with prefixes Ki, Mi, and Gi, respectively.

Thus, 1024 bits should properly be 1 Kib and 1024 bytes should be 1 KiB.

But these have only received sparse adoption for the simple reason that people in the know can generally figure out which is meant and are aware of the issue, while people not in the know are hopelessly confused by the new prefixes.

That this is so is easily exemplified by the fact that many people can't comprehend the difference between a bit and a byte. Call up virtually any ISP as though you were ordering high speed internet service and the person you talk to will almost certainly tell you that you are getting ten megabytes per second when they really mean ten megabits per second. If you press them on it, they will tell you that it says ten megabytes per second, but if you are real explicit and ask them if it is 10 Mb/s or 10 MB/s, they will tell you that it is 10 Mb/s. So a factor of 8 is a bit more of an issue than whether or not there is a factor of 1.04, yet they are clueless as to the difference.

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