This is the pressure at sea-level (the average level of the ocean over the entire earth). The average sea-level air pressure is 1,013 millibars, 760 mm Hg, 101 kilopascals, 29. 92 inch of mercury, 14. 7 lb/ sq in, or 1. 00 atmosphere. The normal range of sea level air pressure worldwide is 970-1040 millibars.