The present invention concerns a method for determining the efficiency of the amplification of a target nucleic acid comprising the following steps: (i) preparation of a dilution series of the target nucleic acid, (ii) amplifying the target nucleic acid under defined reaction conditions, the amplification being measured in real-time (iii) setting a defined signal threshold value, (iv) determining the cycle number at which the signal threshold value is exceeded for various dilutions, (v) determining the amplification efficiency as a function of the amount of original target nucleic acid. The present invention also concerns a method for the quantification of a target nucleic acid in a sample in which the efficiency of the amplification reaction is determined in this manner and is taken into account in the quantification.