Method for detecting the rotor speed of a wind turbine , and the wind turbine includes an aerodynamic rotor that can be operated at a variable rotor speed, and a speed measuring device for detecting the rotor speed, with an increment carrier with increments distributed over a circumference, wherein the increment carrier is mechanically coupled to the rotor in such a way that one revolution of the increment carrier corresponds to one revolution of the rotor , and a measuring sensor for detecting the speed of the increment carrier , wherein the measurement sensor records times as increment times for each increment in which the increment carrier rotates one increment at a time, For a corrected measurement, the following steps are provided when the rotor rotates : a) for each increment determine a difference time as the difference between a currently measured increment time and a mean time, where the mean time is an arithmetic mean over all increment times recorded in one or more complete revolutions of the increment carrier for each increment, and b) determine an increment correction value for each increment for each increment depending on the difference time of the increment in question formed in step (a), and for determining a corrected rotor speed a corrected increment time is determined for each increment by correcting the current increment time as a function of the increment correction value, and a corrected rotor speed is determined as the current rotor speed from the corrected increment time. an aerodynamic rotor that can be operated at a variable rotor speed, and a speed measuring device for detecting the rotor speed, with an increment carrier with increments distributed over a circumference, wherein the increment carrier is mechanically coupled to the rotor in such a way that one revolution of the increment carrier corresponds to one revolution of the rotor , and a measuring sensor for detecting the speed of the increment carrier , wherein the measurement sensor records times as increment times for each increment in which the increment carrier rotates one increment at a time, an increment carrier with increments distributed over a circumference, wherein the increment carrier is mechanically coupled to the rotor in such a way that one revolution of the increment carrier corresponds to one revolution of the rotor , and a measuring sensor for detecting the speed of the increment carrier , wherein the measurement sensor records times as increment times for each increment in which the increment carrier rotates one increment at a time, a) for each increment determine a difference time as the difference between a currently measured increment time and a mean time, where the mean time is an arithmetic mean over all increment times recorded in one or more complete revolutions of the increment carrier for each increment, and b) determine an increment correction value for each increment for each increment depending on the difference time of the increment in question formed in step (a), and for determining a corrected rotor speed a corrected increment time is determined for each increment by correcting the current increment time as a function of the increment correction value, and a corrected rotor speed is determined as the current rotor speed from the corrected increment time. a corrected increment time is determined for each increment by correcting the current increment time as a function of the increment correction value, and a corrected rotor speed is determined as the current rotor speed from the corrected increment time. <EOS>