A system for calculating a first mass value indicative of a first mass of a vehicle is provided, wherein the vehicle has a vehicle interface capable of providing fuel data indicative of a rate at which fuel is being consumed by an engine of the vehicle at each point in time. The system includes: an interface coupled with the vehicle interface, the interface configured for: receiving the fuel data; and receiving movement data indicative of a movement of the vehicle at the each point in time; and a data processing system configured for: deriving a plurality of mass values from the fuel data and the movement data, each mass value corresponding to a respective point in time; and calculating, using the plurality of mass values, the first mass value indicative of the first mass of the vehicle.