An empirical method based on the equation of the sigmoid shape of the conversion –temperature curve was applied on the pyrolysis of water hyacinth to produce biochar. The dried material was manually ground to pass 147μm screen and its calorific value determined. The material was heated in nitrogen in a thermal analyzer at four different heating rates (5 to 20oC.min-1). The TG trace obtained was used to calculate the conversion to biochar which was completed at about 400oC with subsequent cracking up to about 500oC. The produced biochar was characterized by EDX and its calorific value determined. Equations were obtained for the sigmoid shapes to simulate the conversion – temperature curves at the four heating rates. A simple method was then used to predict the kinetic parameters of biochar formation and cracking relying on the sigmoid shapes of conversion curves. These were found to be compatible with that calculated by the Coats – Redfern method.