What is the atmospheric pressure at an altitude of 30000 feet?

At an altitude of 30,000 feet, the atmospheric pressure is significantly lower than at sea level, typically around 4.3 pounds per square inch (psi) or approximately 29.3 inches of Mercury (inHg). This equates to about 0.14 times the standard atmospheric pressure at sea level, which is 1013.25 hPa. The decrease in pressure is due to the thinning of the atmosphere as altitude increases.