To work out your power-to-weight ratio figure, simply divide your maximum power output (in watts) by your body mass in kilograms (kg). For example, an 80kg rider with a maximum sustainable power output of 280 watts has a power-to-weight ratio of 3.5 watts per kilo (commonly abbreviated as 3.5W/kg or 3.5W. kg-1).Feb 3, 2020