A method and apparatus for regulating the vacuum supply to calibration tools which include at least one dry calibration tool and at least one calibration bath, wherein at least one vacuum pump is brought into contact with a calibration tool in order to extract air from the calibration tool, the pressure in the tool being regulated to a target value by means of a control valve. Several vacuum pumps extract air from a common pressurized container, and the air is extracted from at least one dry calibration tool by a first control valve in the common pressurized container and in addition the air is extracted from at least one calibration bath by a second control valve in the common pressurized container.