Pressure sensors for plantar pressure measurement – either based on resistive or capacitive technology – should guarantee for high accuracy and reliability, since they are increasingly used both in scientific research tools in the field of biomechanics and in diagnostic tools in clinics. The above requirements not only entail a mandatory in-factory calibration, but also periodic in-the-field calibrations to verify the maintenance of an adequate quality level. The present study deals with the design, construction and validation of a valuable pneumatic calibration device suitable both for factory calibration – where each pressure sensor must be wholly characterized over the used pressure range – and for fast, easy in-the-field calibration - where sensor matrices must be tested in their final commercial assembly, and single pressure values are needed as well as force and center of pressure (COP) estimation. The described test device is based on a pneumatic circuit including an on-off valve and a proportional valve for the application of pressure in the range 0-700kPa under static and dynamic conditions over a small squared area, in the frequency range 0.5-1Hz. The test device is also equipped with a special tool to apply a known vertical force through 3 round supports of a graduated round table, to assess accuracy and precision of COP estimation. Correctness of table position is assured by an ad hoc positioning system.