A device for measuring the lifetime of a blade (10) of a lawnmower is described； the device comprising at least a first sensor (2) configured to detect the impacts of the blade with stones or other objects, and at least a second sensor (40) configured to detect the lawnmower motor rotation revolutions, and a control unit (3). The control unit comprises first means (31, 32) configured to measure the intensity of the single impacts of the lawnmower blade in response to the detected data of said first sensor and configured to measure the rotation speed of the blade in response to the detected data of said second sensor； the control unit comprising second means (33) configured to count the blade working hours, and it being configured to process the lifetime of the blade as a function of the carried out measures and of the counted working hours of the blade. (Fig. 1)
