Mathematical modeling plays a major role in assessing, controlling, and forecasting potential outbreaks. In this study, the curve fitting method is taken into consideration. We give the method of the least squares as a standard approach in regression analysis that estimates the attainable maximum (peak value) of the Coronavirus infection that started in Wuhan, China, and spread to the world in a short time period. Finally, we demonstrated its applications for three countries and presented results clearly that earns further detailed disquisition.