Okay when I learned this I felt somehow sad.
but when ISPs offer you eg 50mbps, they don't really mean that you'll download with 50 MBytes/sec
because mbps = mega bits per second
8 bits = 1 byte
in this case 1 mega byte = 8 mega bits
So if we do 50 mega bits ÷ 8 it gives us 6.25mega bytes
-Yeah but that's not my download speed!
The speed also depends on the distance between the ISP's location and you so you should perform a speedtest
and then do result ÷ 8 to find the true download speed.
I think most people will know this but this is the chillout room so I just wrote it.