Kilobyte = 1024 bytes of data
Megabyte = 1024 Kilobytes
Gigabytes = 1024 Kilobytes
The “S” represents per second
1 byte = 8 bits
A bit is a binary (base 2) number so it’s commonly resresented as an X or a 0
All computer process in binary.
Edit:
Now that I have time let me explain Internet speed a little better. Over the Internet data is transmitted in packets. Generally a packet size (or referred to as MTU) is 1500 bytes. So the sending system chops up the data in 1500 byte segments which can be reassembled by the receiving system. Along with that packet is a checksum that for discussion purposes is after adding up all the values of that packet to make a number which is compared to the checksum which is attached to the end of the packet transmission.
If the sum of the data packet = the checksum an "OK" or an "ACK" is returned to the sending system to say "packet received intact, send me the next packet or no it's not right, resend that packet" Either way the sending system will wait for a response.
So that's why file sharing or P2P or torrents became a problem. Residential cable lines were only capable of handling X amount of bandwidth combined both ways. Because the nature of sharing the connection to the NOC (network operations center), cable companies provisioned that line so most of the available bandwidth was downstream, that is from sender to you because normally all that was needed for the most part was the capacity to return ACKs..
So instead, because of file sharing the upstream bandwidth was "flooded" or completely used to share files to remote receivers. As a result, there wasn't any capacity left to quickly send those ACK acknowledgements to senders of downstream packets and people's Internet service degraded into dial up speeds as a result. These days it's not such a problem, fiber lines are completely symmetrical same speed up as down and cable has become much better.
My point here is speed isn't always just dependant on what your line may be provisioned for there are other factors at play.
Before the nitpicking starts I did overly simplify the process, but the fundamentals remain correct and it gets the idea across.