At first glance, one might simplistically assume that if the maximum payload of a truck is reduced by x%, the total amount of goods that a fleet can transport would decrease by the same percentage. For example, if a diesel truck has a maximum payload of 45,000 lbs (20.41 tonnes) and a battery electric truck (BET) has a reduced maximum payload of 30,000 lbs (13.6 tonnes) due to a 15,000 lb (6.8 tonnes) battery, one might expect that approximately 50% more BETs would be required to transport the same amount of goods. In reality, the payload weight distribution is quite broad, only a small fraction of the trucks is at the weight limit. Meanwhile, for the other trucks, the maximum payload is limited by volume, or trucks are not completely filled. Therefore, we need fewer extra BET trucks than the simplistic estimate from the reduction in max payload. Explained below is our fleet-based methodology to compute a realistic payload penalty where we calculate the total number of battery electric trucks required to replace a diesel fleet with equal cargo capacity.