A device (200) for measuring a milk volume yielded from an animal during a milking process, comprising a container (201), a supply line unit (202), a delivery unit (211), a level measurement device (219), a control unit (236) and an evaluation unit (237). The supply line unit is designed for supplying milk into the container and can be connected to a milking tool of a milking machine. The delivery unit is designed for delivering milk out of the container and can be connected to a milk line of the milk machine that can be charged with a milking vacuum. The delivery unit comprises means (213) for changing the size of a drain opening through which the milk flows during delivery out of the container. The drain opening can be adjusted to at least two sizes, which allow a flow of milk through the drain opening. The level measurement device is designed to measure a level of milk in the container. The control unit is designed to control the means for changing the size of the drain opening in dependence on the level of milk in the container determined by the level measurement device in order to adjust the size of the drain opening so that the level remains in a specified range. The evaluation unit is designed to calculate a milk flow into the container from the adjusted size of the drain opening and the level measured by the level measurement device.
