How to calculate transfer rate and needed bandwidth
Your calculations are wrong. You have misunderstood the concept. The files may contain an amount of bits as you calculated but transferring that information is a bit different.

First of all, you send information as PACKETS. Here is an example packet type which is being used in Bluetooth.



The only place you send the actual information is called PAYLOAD. As you can see, payload is occupying a smaller area than you expected in a packet. The size of payload can smaller or larger depending which type of packet you are using, or which type of standards you are working with etc. And your bit rate is determined by which modulation type you use, how many bits your one symbol contains etc.

And not to forget, if your conditions are not perfect (which is the general situation) you WILL send some packets which is corrupt and you need to send them again. Which also reduces your actual bit-rate.

So there is different calculations for different combinations of the different techniques. 

I hope the answer is clear.

As always,
Have a nice day.