| Calculate Altitude & Pressure Parameters | |
|---|---|
| Select Answer Mode |
|
Click save settings to reload page with unique web page address for bookmarking and sharing the current tool settings
Change the answer mode for this tool by selecting altitude (H), altitiude difference (ΔH), pressure (P), or pressure difference (ΔP) as the parameter to calculate instead
Featured atmospheric pressure measurement products
Non-vented submersible absolute range pressure and barometric sensor for measuring 10m water level - Learn how to use a non-vented submersible sensor with a barometric pressure sensor for accurate water level measurement in challenging installations.
Atmospheric, Barometric Range Scaled Volts Signal Out Pressure Transducers - Precision monitor atmospheric pressure fluctuations with these specialized transducers, engineered to provide a scaled voltage output directly proportional to the measured barometric pressure.
Related Tools
- US Standard Atmosphere Altitude and Pressure Calculator
- Pressure unit conversion
- Height unit conversion
User Guide
This tool which is based on the icao standard atmosphere model will calculate the air pressure at a height above or below sea level, the altitude from the atmospheric air pressure at the same level, the pressure difference between two altitudes, and the altitude difference between two atmospheric pressures.
The method and formulas used are based on the ICAO Standard Atmosphere 1993 model for use from a height of 5000 metres below mean sea level up to a height of 80,000 metres above mean sea level. The atmospheric model assumes the air is a dry ideal gas, with an atmospheric pressure of 101325 Pa and a temperature of 288.15 K at mean sea level.
In reality the atmospheric pressure, temperature & humidity level in the air are constantly changing, therefore the accuracy in determining the true altitude is limited by this. However despite the dynamic nature of the atmosphere, standard atmosphere models serve as a way of standardising measuring instruments. If every measurement instrument is calibrated with the same atmospheric model the readings can be directly compared.
Featured vacuum range absolute pressure measurement products
300 mmHg absolute vacuum pressure transducer with 10 volts output - Absolute pressure transducer for precise vacuum measurement. 0-300 mmHg range, 0-10V output, high accuracy.
Baroli 02P Low Range Flush Diaphragm Digital Pressure Gauge - All stainless steel 316L hygienic digital display pressure gauge for measuring low range pressures with ranges from 0-100 mbar up to 0-40 bar.
Formulas
The formulas used by this icao standard atmosphere altitude and air pressure calculator to determine each individual parameter are:
For βb ≠ 0:
P = Pb · (1 + (βb · (H – Hb) / Tb))-g / (βb · R)
H = ((((P / Pb) –βb · R / g – 1) / βb) * Tb) + Hb
For βb = 0
P = Pb · e-g · (H – Hb) / (R · Tb)
H = (ln(P / Pb) · R · Tb / -g) + Hb
ΔP = P2 – P1
ΔH = H2 – H1
Symbols
- P = Atmospheric pressure at altitude H
- ΔP = Atmospheric pressure difference from H1 to H2 altitude
- Pb = Atmospheric pressure at interfaces between atmosphere transitional layers from b = 0 to 6
- H = Geopotential altitude relative to mean sea level
- ΔH = Geopotential altitude difference from P1 to P2 atmospheric pressure
- Hb = Geopotential altitude from mean sea level of interfaces between atmosphere transitional layers from b = 0 to 6
- Tb = Reference temperature at interface between atmosphere transitional layers from b = 0 to 6
- βb = Standard temperature lapse rate to change reference temperature (Tb) between atmosphere transitional layers from b = 0 to 6
- g = Standard acceleration due to gravity = 9.90665 m/s2
- R = Specific gas constant = 287.05287 J/K·kg, constant value defined by ICAO Standard Atmosphere 1993, and derived from ideal gas law equation; P = ρ·R*·T/M0, where P = 101,325 Pa, ρ = 1.225 kg/m3, R* = 8,314.32 J/K·kmol, T = 288.15 K, M0 = 28.964420 kg/kmol), P/(ρ·T) = R* / M0 = R
Atmospheric Layer Constants
| b | Height (m) | Pressure (Pa) | Reference Temperature (K) | Lapse Rate (K/m) |
|---|---|---|---|---|
| 0 | 0 | 101,325 | 288.15 | -0.0065 |
| 1 | 11,000 | 22632.0401 | 216.65 | 0 |
| 2 | 20,000 | 5474.87742 | 216.65 | 0.001 |
| 3 | 32,000 | 868.015777 | 228.65 | 0.0028 |
| 4 | 47,000 | 110.905773 | 270.65 | 0 |
| 5 | 51,000 | 66.9385281 | 270.65 | -0.0028 |
| 6 | 71,000 | 3.95639216 | 214.65 | -0.002 |
Altitude (H)
This is the geopotential height above or below mean sea level.
Pressure (P)
This is the absolute pressure of air at a particular level in the atmosphere.
Altitude 1 (H1)
This is the initial altitude used in calculating the atmospheric pressure difference between two altitudes.
Altitude 2 (H2)
This is the final altitude used in calculating the atmospheric pressure difference between two altitudes.
Pressure Difference (ΔP = P2 – P1)
This is the atmospheric pressure difference when changing altitude from H1 to H2.
Pressure 1 (P1)
This is the initial atmospheric pressure used in calculating the altitude difference between two different elevations.
Pressure 2 (P2)
This is the final atmospheric used in calculating the altitude difference between two different elevations.
Altitude Difference (ΔH = H2 – H1)
This is the altitude difference which corresponds to the change atmospheric pressure from P1 to P2, due to a change in elevation.
Featured atmospheric pressure measurement products
Barometric pressure sensor for hurricane tracking on uncrewed surface vessel - Barometric pressure measurement in harsh marine environments. This application required a corrosion-resistant, IP67-rated pressure sensor for an uncrewed surface vessel used in hurricane research, capable of withstanding saltwater spray and high humidity.
Barometric & Atmospheric Pressure Gauges - Barometric pressure gauges with ranges up to 2 bar absolute, vital for industrial verification, environmental monitoring, and compensating measurements like humidity, air density, and airflow.