# Converting bytes to bits and then to Mbits

If you have a 100 50KB files that is saved on your hard disk per second, I want to figure out how many Mbits per second this is.

So please correct me if I am wrong:

= 50 * 8 * 1000 = 400 000 bits per second

400 000 bits per second is how many Mbits per second (mega bits per second)?

Is it .4 Mbps transfer rate then?

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Usually if people/Microsoft speaks of "50 KB" the mean "50 KiB" which means 50 * 1024 bytes. – Robert Dec 4 '12 at 16:03
400 Kbps is 40% of 1 Mbps. This would be 0.40 Mbps – Ramhound Dec 4 '12 at 16:03
@Robert : No, and that's why binary prefixes were created. When retailers say "50 kB" they really mean 50kB = 50,000 bytes. But people believe it is "50 kiB" which is equal to 50 * 1024 B = 51,200 bytes = 51.2 kB. Binary prefixes were created to avoid this confusion (where people get less memory than they think). – air-dex Dec 4 '12 at 22:33
@air-dex: But here we are talking about files of 50KB size and common OS I know usually show the value as KiB even if it is labeled "KB". – Robert Dec 5 '12 at 9:36

## 1 Answer

For conversion between bits and bytes, it is easy too :

1 byte = 1B = 8 bits = 8b

For bits, it is the International System of units which uses decimal prefixes. So it is easy to understand :

1Mb = 1 Mega-bits = 1.000.000 bits

However, the decimal prefixes of International System of units must not be counfounded with the binary prefixes system. So do not rely on Robert's comment under the question.

So in your case :

``````50 kB = 50,000 B = 50,000 * 8 b = 400,000 b = 400 kb = 0.4 Mb
``````
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