The invention relates to a pipetting device having tube with an opening at one end for suctioning or discharging a sample fluid, and can be operatively connected to a pressure generation device at the other end. A first electrode is formed on the pipetting device that forms a measuring capacitor together with a second electrode formed by at least one part of the sample fluid and that can be received in the tube and the measuring capacitor is operatively connected to a measuring unit, and the measuring unit is designed to determine a volume of the suctioned or discharged sample fluid according to the capacity of the measuring capacitor. The invention also relates to a fluid processing system having a pipetting device of this type, as well as a method for determining a processed fluid volume during pipetting with a pipetting device of this type.