Where Pabs is absolute pressurePg, is gauge pressure, and Patm is atmospheric pressure. For example,

if your tire gauge reads 34 lb/incz (pounds per square inch), then the absolute pressure is ...

48.7 psi

Explanation:

To get absolute pressure, it's given by getting the sum of atmospheric pressure and gauge pressure. Now for this case, when the tire gauge reading is 34 lb/incz (pounds per square inch) and then adding the atmospheric pressure of 14.7 lb/incz (pounds per square inch) then the absolute pressure will be 34+14.7=48.7 lb/incz (pounds per square inch) which is equivalent to equivalent to 336 kPa