A method of determining payload material density includes a step of determining a capacity volume of a work tool of a machine using an electronic controller of the machine. The work tool is loaded with an initial amount of loaded material matching the capacity volume, and an onboard payload mass calculation algorithm is executed using the electronic controller to determine a mass of the initial amount of loaded material. A density of the initial amount of loaded material is calculated responsive to the mass of the initial amount of loaded material and the capacity volume using the electronic controller. The density of the initial amount of loaded material is stored using the electronic controller, and a productivity datum is calculated responsive to the density of the initial amount of loaded material and a subsequent amount of loaded material.