# 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

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.

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