the only truely safe way to measure you oil level is with the dipstick, when the oil is cold and the car is level. I wouldn't trust any other way and certainly not the oil pressure gauge. Also don't think like some members have in the past that when the oil light comes on, it means time to put some oil in as its low. It doesn't, it means the oil pump is pumping air. It aint good news from now on.
Maybe suck eggs to some but rather safe than sorry