A method for calibrating a thickness gauge, wherein the thickness gauge measures the thickness of a measurement object in a predefinable measuring direction (Z), comprising at least one displacement sensor (1, 2) operating in a contactless or scanning manner, wherein a reference object (3) having a known thickness and shape is moved into at least a partial region of the measurement field of the at least one displacement sensor (1, 2), comprises the following steps with respect to particularly precise and simple calibration. First, at least two independent measurement values are recorded by the at least one displacement sensor (1, 2) in at least two predefinable sites on a first surface of the reference object (3) at predefinable times tj, or as a function of predefinable positions pj of the reference object (3) in the measurement field, where j = 1, 2... Then the tilting or spatial position of the reference object in the measurement field is determined based on the measurement values recorded at the times tj, or as a function of the positions pj of the reference object (3). Then, a further measurement value is recorded by the at least one displacement sensor (1, 2) at a further site located in the measuring direction (Z) on a second surface disposed opposite the first surface, or on a surface region of the reference object (3) disposed opposite the first surface, in order to determine a thickness value of the reference object (3) in the measuring direction (Z).