In a method for determining mass-flow with the aid of a Coriolis mass-flow meter in which mass-flow ({dot over (m)}) is won from the phase difference of two sensor signals X17, X18, three measuring channels K1, K2, K3 are provided for the two sensor signals X17, X18. By selective switching of the sensor signals X17, X18 onto the measuring channels K1, K2, K3, phase error caused by the different signal paths can be determined and taken into consideration when calculating mass-flow ({dot over (m)}).