Method for determining the amount of a nucleic acid in a starting sample, in which - the starting sample is amplified in a system in a first cycle, and a measure of the amplification is acquired as a result value, - the amplification in the system in a respective cycle and the acquisition of a measure of the amplification as a result value for the respective cycle is repeated at least n times, and each cycle is assigned a cycle value for identification, - so that a result data set is produced in which a result value is assigned to a respective cycle value for a multiplicity of cycle values, there being produced from the result data set a data set in which a result value is assigned to a respective cycle value for a plurality of cycle values, the multiplicity of the cycle values included in the result data set being greater than the plurality of the cycle values included in the data set, the sequence of the cycle values of the data set being a subgroup of the sequence of the cycle values of the result data set, and the last cycle value of the sequence of cycle values of the data set being determined as follows: proceeding from a starting cycle value of the result data set for a plurality of consecutive sequences of three cycle values which are respectively denoted as first cycle value, second cycle value and third cycle value within the respectively considered sequence in accordance with their sequential order in the result data set, the sequence is determined, in the case of which - the result value assigned to the second cycle value of the considered sequence is greater than the result value assigned to the first cycle value of the considered sequence, and - the curvature value z, which results from the sum of the result value, assigned to the first cycle value and of the result value assigned to the third cycle value of the considered sequence and the subtraction of twice the result value assigned to the second cycle value of the considered sequence assumes the highest value among the considered sequences, the second cycle value of the sequence which satisfies said requirements being used as last cycle value of the data set. - the starting sample is amplified in a system in a first cycle, and a measure of the amplification is acquired as a result value, - the amplification in the system in a respective cycle and the acquisition of a measure of the amplification as a result value for the respective cycle is repeated at least n times, and each cycle is assigned a cycle value for identification, - so that a result data set is produced in which a result value is assigned to a respective cycle value for a multiplicity of cycle values, - the result value assigned to the second cycle value of the considered sequence is greater than the result value assigned to the first cycle value of the considered sequence, and - the curvature value z, which results from the sum of the result value, assigned to the first cycle value and of the result value assigned to the third cycle value of the considered sequence and the subtraction of twice the result value assigned to the second cycle value of the considered sequence assumes the highest value among the considered sequences,