The present invention relates to a device and method for ascertaining the steering angle (α3) of at least one steerable wheel of a set of steerable wheels of a machine that can be directionally controlled, which machine comprises at least said set of steerable wheels and at least one set of drivable wheels showing a specific wheelbase (a1) relative to said steerable wheels and spaced from one another by a specific track width (b1), wherein by means of an ascertained wheel velocity difference of the two driven wheels a yaw rate (ψ) and a real circle radius (r1) of the driven wheel on the inside of the curve are ascertained. It is then possible to ascertain the steering angle (α) from these values by way of the geometrical relationship of wheelbase (a1) and track width (b1) of the machine.