The device to measure blood pressure is called a "blood pressure meter or sphygmometer" and is composed of an inflatable cuff and a manometer. The cuff restricts blood flow and the manometer measurers the pressure. Manual sphygmomanometers are used with a stethoscope to determine the pressure at which the blood flow is starting, and the pressure at which it is unimpeded.

There are 3 types of sphygmomanometers: digital, with automatic or manual inflation which measurers mean arterial pressure. In the true sense, they derive readings rather than actually measure the blood pressure. There is the digital portable finger blood pressure monitor with automatic inflation which is portable, easy to operate and less accurate. Then we have the gold standard which does not need calibration, is consistently accurate and they are manual, used by trained persons and with mercury manometers.

Because of the accuracy of the manual mercury manometer, it is required in clinics, hospitals (especially important for high risk patients and pregnant women) and pharmaceutical evaluations.