This is a volume calculator written for use with the Meuller Model M 500 gallon milk tank. Each milk tank is supposed to be calibrated on site after being positioned on a stable, level surface. The calculations used here are for a specific tank and so will likely vary if used on any other tank by at least a small amount. Since the tank that this calculator is for isn't used for milk, this calculator inputs inches of milk and outputs gallons and liters of liquid. The calculations are based on the assumption that 1 gallon of milk weighs 8.6lbs, which seems to be the industry standard. None of Muellers documentation indicates an assumed weight.