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ISA Atmosphere Calculator

Find temperature, pressure, and density in the troposphere using the International Standard Atmosphere.

 

T (K)
P (Pa)
Density (kg/m³)

About this calculator

Use this calculator for the dry ISA troposphere from sea level up to 11 km. Temperature drops 6.5 K per kilometre from T₀ = 288.15 K. Pressure follows the hydrostatic ISA power law for dry air (R = 287.05 J/(kg·K), g = 9.80665 m/s²), and density is P / (R T).

At 1000 m you get about T = 281.7 K, P = 8.99×10⁴ Pa and ρ = 1.11 kg/m³. Height is geometric metres above sea level, 0 to 11000. Humidity, weather, and the stratosphere are not in this sketch.

Height (m): Metres above sea level, 0 to 11000.

T (K): Static air temperature.

P (Pa): Static pressure.

Density (kg/m³): ρ = P / (R T).