Disclosed is an ultrasound device for measuring blood flow velocity in a blood vessel of a subject without imaging functionality in the device. The measurement depends upon reflections of a collimated beam of ultrasound from a subject's body part. Received electrical signals representative of the reflected ultrasound energy is used for generating a representation of blood flow at a plurality of predetermined locations in the volume and calculating a first blood flow velocity at each of the locations. The representation of flow is used for delineating the blood flow in the blood vessel in the volume. An angle calculating unit calculates the Doppler angle between the direction of the radiated collimated beam in the delineated blood flow at each point. A velocity calculator calculates a second blood flow velocity at the plurality of points based on the calculated first velocities and the calculated angle at the point.
