In above example, 20 mbps is connection speed. The actual download speed is ~1/8 of the connection speed.
So,
Dowload speed = connection speed / 8
Rearranging the simple mathematical equation
Connection speed = download speed x 8
Torrents softwares show download speeds which can be multiplied by 8 to calculate connection speed.
These are theoretical approximate values calculated in 100% efficiency conditions, the actual values may vary.