A method is described for ascertaining an acceleration of a target or an object with the aid of radar waves. In a first step, at least one radar transmit signal is sent by at least one transmitting device. At least one radar reception signal reflected from a target is received and subsequently conveyed to an evaluation unit. The evaluation unit converts the radar reception signals into digital measuring values and is used for further processing of the digital measuring values. In a further step, the digital measuring values are subjected to a two-dimensional Fourier transform. At least one target reflection is detected on the basis of peak values or selected from a resulting absolute value spectrum or distance-velocity spectrum. At least one distance of a target from the transmitting device and at least one radial velocity of a target in relation to the transmitting device are ascertained based on the distance-velocity spectrum. Subsequently, at least one angle of the at least one target is determined in relation to an alignment of the transmitting device. Based on the determination or computation of the distance, the transverse velocity, and the angle, the particular signal components relevant for the estimation are separated. For at least one target reflection of an actual target or object, after carrying out an inverse Fourier transform, at least one radial acceleration is approximately computed from the remaining again transformed measured values. Furthermore, a radar device is described.