The present invention seeks to solve the problems of determining the mass flow rate of a fluid, like for example milk, where a free flow milk meter is used to determine the expected milk yield which often differs from the actual milk yield. The present invention is a device for determining a mass flow rate of a fluid in a conduit having an inner surface and an outer surface. The device comprises a measuring member, an additional measuring member, a reference measuring member and a processing unit. The measuring member is arranged on the inner or the outer surface of the conduit for determining an electrical conductivity of the fluid in the conduit. The additional measuring member is arranged on the inner or the outer surface of the conduit for determining the electrical conductivity of the fluid at an additional position in the conduit. The reference measuring member is for determining a specific resistance of the fluid in the conduit. The processing unit is for determining the mass flow rate of the fluid in the conduit on the basis of the determinations of the electrical conductivity and specific resistance by the measuring member, the additional measuring member, and the reference measuring member. Determination of the electrical conductivity of the fluid in the conduit takes place via the measuring member and the additional measuring member on the basis of a signal supplied externally relative to the measuring member and the additional measuring member.
