Equations for Pressure Versus Altitude
Altitude	Pressure Equation
0 km < H ≤ 11 km	P(Pa) = 101325 [ 288.15 − 6.5(H) ———————— 288.15 ]5.2558
(0 ft < H ≤ 36.1 kft)	(P(Pa) = 101325 [ 288.15 − 1.9812 · H —————————— 288.15 ]5.2558)
11 km < H ≤ 20 km	P(Pa) = 22632.41 · exp [ − (H − 11) ———————— 6.34162 ]
(36.1 kft < H ≤ 65.62 kft)	(P(Pa) = 22632.41 · exp [ − (H − 36.089) —————————— 20.806 ])
20 km < H ≤ 32 km	P(Pa) = 5475.052 [ 216.65 —————————————— 216.65 + (H − 20) ]34.16
(65.62 kft < H ≤ 105 kft)	(P(Pa) = 5475.052 [ 216.65 ————————————————————— 216.65 + (0.3048 · H − 20) ]34.16)