System for the computer-aided estimation or determination of a value for the total mass of a vehicle system, which comprises a towing vehicle and, if necessary, at least one trailer coupled with the towing vehicle, characterized in that the system a) has a sensor device, which is configured so that its sensor signals represent physical data of the vehicle system, which varies as a function of a loading of the vehicle system and a number of trailers coupled with the towing vehicle and on the basis of which it can be detected whether a loading of the vehicle system and a number of trailers coupled with the towing vehicle have changed or not changed between a first point in time and at least one second point in time later than the first point in time, and b) has an processing device, which is configured such that, in particular independently of the physical data, it estimates or determines a first value for the total mass of the vehicle system at a first point in time as part of a first estimation or determination, wherein c) the processing device is further configured so that it can detect, on the basis of the physical data, whether the loading of the vehicle system and the number of trailers coupled with the towing vehicle have changed or not between the first point in time and the at least one second point in time, and in that d) the processing device is further configured such that it - maintains the first value as the valid value for the total mass of the vehicle system or uses it as an initial value for a further determination or estimation of the total mass of the vehicle system, if it has detected, on the basis of the physical data, that between the first point in time and the second point in time no significant change in the loading of the vehicle system and no change in the number of trailers coupled with the towing vehicle, but - as part of a second estimation or determination subsequent to the first estimation or determination estimates or determines a second value for the total mass of the vehicle system, in particular independently of the physical data, and discards the first value if it has detected on the basis of the physical data that a change in the loading of the vehicle system and/or a change in the number of trailers coupled with the towing vehicle has occurred between the first point in time and the second point in time. a) has a sensor device, which is configured so that its sensor signals represent physical data of the vehicle system, which varies as a function of a loading of the vehicle system and a number of trailers coupled with the towing vehicle and on the basis of which it can be detected whether a loading of the vehicle system and a number of trailers coupled with the towing vehicle have changed or not changed between a first point in time and at least one second point in time later than the first point in time, and b) has an processing device, which is configured such that, in particular independently of the physical data, it estimates or determines a first value for the total mass of the vehicle system at a first point in time as part of a first estimation or determination, wherein c) the processing device is further configured so that it can detect, on the basis of the physical data, whether the loading of the vehicle system and the number of trailers coupled with the towing vehicle have changed or not between the first point in time and the at least one second point in time, and in that d) the processing device is further configured such that it - maintains the first value as the valid value for the total mass of the vehicle system or uses it as an initial value for a further determination or estimation of the total mass of the vehicle system, if it has detected, on the basis of the physical data, that between the first point in time and the second point in time no significant change in the loading of the vehicle system and no change in the number of trailers coupled with the towing vehicle, but - as part of a second estimation or determination subsequent to the first estimation or determination estimates or determines a second value for the total mass of the vehicle system, in particular independently of the physical data, and discards the first value if it has detected on the basis of the physical data that a change in the loading of the vehicle system and/or a change in the number of trailers coupled with the towing vehicle has occurred between the first point in time and the second point in time. - maintains the first value as the valid value for the total mass of the vehicle system or uses it as an initial value for a further determination or estimation of the total mass of the vehicle system, if it has detected, on the basis of the physical data, that between the first point in time and the second point in time no significant change in the loading of the vehicle system and no change in the number of trailers coupled with the towing vehicle, but - as part of a second estimation or determination subsequent to the first estimation or determination estimates or determines a second value for the total mass of the vehicle system, in particular independently of the physical data, and discards the first value if it has detected on the basis of the physical data that a change in the loading of the vehicle system and/or a change in the number of trailers coupled with the towing vehicle has occurred between the first point in time and the second point in time.