A fluid metering system for accurately and consistently mixing two or more fluids together. The fluid metering system generally includes a closed loop feedback system that monitors the flow rate of the water and the volume of liquid chemical added to the water over a period of time. Based on the measured amount of chemical added to the water over a period of time, the system calculates whether or not an adjustment is required for the next addition of chemical to the water. The present invention utilizes a measuring tube that is filled with a chemical wherein a pressure sensor measures the pressure of the chemical in the measuring tube when filled and after being emptied to calculate the total volume of chemical added to the water.