A method for determining the mass and the centre of mass of a demountable platform, comprising: - using a hooklift to lift the demountable platform from the ground onto a vehicle, - measuring, during the lifting of the demountable platform, a physical quantity that varies as a function of the movement of the hooklift, - determining, at predetermined values of the physical quantity, values of the load force of a main cylinder of the hooklift, - providing a mathematical model of the load force of the main cylinder as a function of the physical quantity, the mathematical model comprising a set of constants related to the physical dimensions of the hooklift, a first parameter for the mass of the demountable platform, a second parameter for the longitudinal position of the centre of mass of the demountable platform and a third parameter for the vertical position of the centre of mass of the demountable platform, characterised in that the method comprises: - setting initial values for the parameters, - calculating with the mathematical model the values of the load force at the predetermined values of the physical quantity, - calculating a difference between the determined and calculated values of the load force, - if the difference is larger than a predetermined threshold, repeating the following steps until the difference becomes smaller than the predetermined threshold: - changing at least one of the values of the parameters, - recalculating with the mathematical model the values of the load force at the predetermined values of the physical quantity, and - recalculating the difference between the determined and calculated values of the load force; - selecting the value of the first parameter as the mass of the demountable platform, the value of the second parameter as the longitudinal position of the centre of mass of the demountable platform, and the value of the third parameter as the vertical position of the centre of mass of the demountable platform. - using a hooklift to lift the demountable platform from the ground onto a vehicle, - measuring, during the lifting of the demountable platform, a physical quantity that varies as a function of the movement of the hooklift, - determining, at predetermined values of the physical quantity, values of the load force of a main cylinder of the hooklift, - providing a mathematical model of the load force of the main cylinder as a function of the physical quantity, the mathematical model comprising a set of constants related to the physical dimensions of the hooklift, a first parameter for the mass of the demountable platform, a second parameter for the longitudinal position of the centre of mass of the demountable platform and a third parameter for the vertical position of the centre of mass of the demountable platform, - setting initial values for the parameters, - calculating with the mathematical model the values of the load force at the predetermined values of the physical quantity, - calculating a difference between the determined and calculated values of the load force, - if the difference is larger than a predetermined threshold, repeating the following steps until the difference becomes smaller than the predetermined threshold: - changing at least one of the values of the parameters, - recalculating with the mathematical model the values of the load force at the predetermined values of the physical quantity, and - recalculating the difference between the determined and calculated values of the load force; - changing at least one of the values of the parameters, - recalculating with the mathematical model the values of the load force at the predetermined values of the physical quantity, and - recalculating the difference between the determined and calculated values of the load force; - selecting the value of the first parameter as the mass of the demountable platform, the value of the second parameter as the longitudinal position of the centre of mass of the demountable platform, and the value of the third parameter as the vertical position of the centre of mass of the demountable platform.