ISO 2533 / ICAO Standard Atmosphere (ISA) Calculator & Table
Lookup international standard atmosphere temperature, pressure, density, and speed of sound.
Input Parameters
Calculation Results
Visual Growth Breakdown
Formula & How ISO 2533 / ICAO Standard Atmosphere (ISA) Calculator & Table Works
The International Standard Atmosphere (ISO 2533 / ICAO Document 7488) defines a standardized atmospheric model with sea level baseline conditions of 15°C (288.15 K), 1013.25 hPa (29.92 inHg), and 1.225 kg/m³ air density, with a constant troposphere temperature lapse rate of 1.98°C per 1,000 ft (6.5°C per 1,000 m) up to the tropopause at 36,089 ft (11,000 m).
- Enter Altitude (ft) (ft): Input your target parameter value.
- Apply Formula: Calculate using
T = 288.15 - 0.0065h(m) | P = 1013.25 × (T/288.15)^5.25588 | ρ = (P×100) / (287.058×T) | a = 20.05√T. - Review Results: View exact computed answers, metrics, and worked mathematical proofs.
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Frequently Asked Questions (FAQs)
What is the standard sea level temperature and pressure?
Standard sea level conditions are 15°C (59°F / 288.15 K) temperature, 1013.25 hPa (29.92 inHg / 14.696 psi) pressure, and 1.225 kg/m³ air density.
What is the standard temperature lapse rate in aviation?
In the troposphere (surface up to 36,089 ft / 11,000 m), temperature decreases at standard 1.98°C per 1,000 ft (approx 2°C per 1,000 ft) or 6.5°C per 1,000 metres.
What happens to temperature above the tropopause?
Above 36,089 ft (11,000 m) in the lower stratosphere, the temperature remains isothermal at -56.5°C (216.65 K) up to 65,617 ft (20,000 m).
Authoritative Standards & Verified Reference Citations
Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:
CASR Part 91 general operating and flight rules, Part 121 fuel reserves, and flight crew licensing standards.
Aviation weather services, standard atmosphere (ISA) profiles, METAR/TAF aerodrome weather reports.
Aeronautical Information Publication (AIP), En Route Supplement Australia (ERSA), and airspace procedures.
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