What is the standard atmospheric pressure in inches of mercury (in.Hg) at sea level?

What is the standard atmospheric pressure in inches of mercury (in.Hg) at sea level?

• A. 29.50
• B. 30.20
• C. 31.00
• D. 29.92

Answer: (D)

Standard atmospheric pressure at sea level is 29.92 inches of mercury. This value is the reference used in aviation and meteorology to define the standard atmosphere, so instruments like the altimeter can be calibrated and provide consistent readings. It corresponds to about 1013.25 hPa. Values higher or lower than 29.92 inHg would indicate pressures above or below the standard, leading to different instrument indications if used as the reference. Using 29.92 inHg keeps altitude and weather readings aligned across flights and charts.

Standard atmospheric pressure at sea level is 29.92 inches of mercury. This value is the reference used in aviation and meteorology to define the standard atmosphere, so instruments like the altimeter can be calibrated and provide consistent readings. It corresponds to about 1013.25 hPa. Values higher or lower than 29.92 inHg would indicate pressures above or below the standard, leading to different instrument indications if used as the reference. Using 29.92 inHg keeps altitude and weather readings aligned across flights and charts.