For those of you who are horrid at math like I am googles unit conversion is a great help. Want to know how many GB 1Mbps is in a month? Simple just ask google. Well I like to have the ability even when I am not online and I found units. Its in the debian repository and oh so easy to use.

units -t '1Mbps' 'GB/month'
328.71798
units -t '1hour' 'seconds'
3600