Systems and methods for determining a weight of a quantity of fluid, or a flow rate of the fluid by weight. An acoustic sensor positioned on an exterior wall of a vessel containing the fluid determines a fill level of the fluid. A computerized device calculates a weight of the quantity of fluid using a size of the vessel, the determined fill level, a temperature of the fluid, and the fluid identity and/or a fluid density. Flow rate of the fluid through a pipe is determined using two or more acoustic sensors positioned at different locations on a pipe, and a temperature sensor. A computer calculates a differential time of flight of the fluid based on readings of the acoustic sensor, a distance therebetween, the temperature sensor, the pipe volume, and the fluid identity and/or a fluid density. A flow by weight of the quantity of fluid is determined.