Micropipettes or piston pipettes are used to make the most of volume measurements in fields like health, chemistry, biology, pharmacy and genetics. Laboratories must ensure that obtained results using these instruments are reliable, for that is necessary to calibrate micropipettes using the correct method and estimate uncertainties. The objective of this work is to present the best method to calibrate micropipettes according to the describe measurement conditions. A model for the calculation of the measurement uncertainty is also described.