The invention relates to a method for measuring the tenacity K
c of a material, comprising the following steps: placing a sample of said material, having the shape of a parallelepiped rectangle through the middle of which a central hole extends, between two jaws of a clamping device, each of said jaws engaging with a distant end of the sample; moving the two jaws together so as to exert a force at each of said ends until the sample has completely broken; measuring the variations during the clamping on the basis of the time of the clamping force exerted at each end of the sample; determining the maximum value F
0 of said clamping force; marking three separate areas on the surface of one of the breaking surfaces, i.e. a first area close to the hole having a first type of embossment, a second area having a second type of embossment, and a third area having a third type of embossment that is less pronounced than the second type; measuring the distance L
0 between the edge of the hole and a transition line separating the second area from the third area; and calculating the parameter K
c on the basis of the force F
0 and distance L
0 .