Abstract A calibration apparatus where the pressure is generated dynamically was designed for the pressure range (10 −5 –10 2 ) Pa. It is pumped by a combination of a turbomolecular pump (TMP) and a rotary vane pump. It is easy to control the generated pressure by controlling the calibration gas throughput by means of a precise variable leak valve up to the pressure of approximately 1 Pa when pumped by the TMP. To generate the pressure even up to values in the order of 10 Pa, a simple and reliable arrangement was used: the main valve over the TMP was closed entirely and the vessel was pumped through a small conductance. Estimation of the conductance value was performed. The experimental results were in good agreement with the estimation.