A method and a device are described for determining the rotational direction and/or rotational speed of a rotatable body on the basis of a sine signal and cosine signal, which is assignable to the rotational direction and/or rotational speed of the rotatable body and are output by a sensor, having at least one of the following steps: recording a sine signal and cosine signal, which is assignable to the rotational direction and/or rotational speed, at a point in time; determining a phase value from the sine signal and cosine signal; recording sine signals and cosine signals, which is assignable to the rotational direction and/or rotational speed, at points in time; determining phase values from the corresponding sine signals and cosine signals; calculating phase differences from the phase values and the phase value; and determining the rotational direction and/or rotational speed from the phase differences on the basis of a Vernier method.