A fluid warming device has a heat exchange body having an input port and an output port and conducts fluid from the input port to the output port. The fluid warming device has a heater assembly configured to transfer heat to the heat exchange body. The fluid warming device may also have a temperature sensor for measuring a temperature of the heater assembly, and a power sensor for measuring a power to the heater assembly. The fluid warming device also has a controller connected to the temperature sensor and the power sensor. The controller calculates a fluid flow rate and a total volume of fluid delivered through the heat exchange body based on the temperature and the power.
