To provide a controller and a control method for an internal combustion engine capable of reducing the calculation error of recirculation exhaust gas amount due to changes with time of the internal combustion engines, and humidity change of intake air, and also capable of reducing the calculation error of recirculation exhaust gas amount at transient operation. The controller and the control method for the internal combustion engine calculates humidity detecting EGR rate based on intake-air humidity and manifold humidity, calculates humidity detecting opening area which realizes humidity detecting recirculation flow rate calculated based on humidity detecting EGR rate, calculates learned opening area corresponding to present opening degree of EGR valve using learning value of opening area calculated based on humidity detecting opening area, and calculates flow rate of recirculation exhaust gas for control based on learned opening area.