The gauge pressure is the difference between absolute pressure and atmospheric pressure.
absolute pressure is 0.
Subtract atmospheric pressure from absolute pressure to get gauge pressure.
The difference in pressure between absolute and gauge pressure.
gauge pressure 206kPa = 307kPa absolute pressure
i need to explain what an absolute pressure gauge measures
The Bourdon gauge indicates Gauge pressure, not absolute pressure.
Absolute pressure = gauge pressure + atmospheric pressureWhen using a pressure gauge, like when measuring the pressure of the air in a tire, the gauge is actually reading the difference between the atmospheric pressure and the atmospheric pressure. So if the gauge measures 30 psi, and taking atmospheric pressure at about 14.7 psi, the absolute pressure in the tire is actually about 44.7 psi. If the tire is flat, then the gauge will read zero psi, but there is not a vacuum - there is still some air present in the tire, and the absolute pressure of this air is the same as the atmospheric pressure (about 14.7 psi).See related link: Guide to the Measurement of Pressure and Vacuum.
vacuum pressure gauge
Gauge pressure is what you get when you take the reading from your tire pressure gauge. Absolute pressure is the pressure inside your tires plus the atmospheric pressure, which is roughly; 14.7 psi, 101.3 kPa (kilo-Pascals), or one atmosphere. Absolute pressure measures all of the pressure on your tires, inside and out, whereas gauge simply measures the pressure inside the tire.