| 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
DMP331 Precision Pressure Transmitter - Stainless steel pressure transmitter with ranges from 100mbar up to 40 bar gauge or absolute. Special options for ATEX , SIL2 and compound ranges.
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.
Related Tools
- ICAO Standard Atmosphere Altitude and Pressure Calculator
- Pressure unit conversion
- Height unit conversion
User Guide
This tool which is based on the us 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 US Standard Atmosphere 1976 model for use from a height of 5000 metres below mean sea level up to a height of 84,852 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
IMP Ceramic Strain Gauge Pressure Transducer - Ceramic strain gauge pressure transducer with a 2mV/V or 10mV/V output signal in pressure ranges from 1 bar up to 700 bar gauge or absolute.
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.
Formulas
The formulas used by this us standard atmosphere altitude and air pressure calculator to determine each individual parameter are:
For Lb ≠ 0:
P = Pb · (Tb / (Tb + (Lb · (H – Hb))))(g · M) / (R* · Lb)
H = (((Tb / (P / Pb)(R* · Lb) / (g · M)) – Tb) / Lb) + Hb
For Lb = 0
P = Pb · e-g · M · (H – Hb) / (R* · Tb)
H = (ln(P / Pb) · (R* · Tb) / (-g · M)) + 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
- Lb = 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
- M = Molar mass of Earth’s atmosphere = 0.0289644 kg/mol
- R* = Universal gas constant = 8.31432 J/mol·K (* Defined by US Standard Atmosphere 1976 which differs from the current SI defined value of 8.31446261815324)
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 | 22,632.064 | 216.65 | 0 |
| 2 | 20,000 | 5,474.88867 | 216.65 | 0.001 |
| 3 | 32,000 | 868.018685 | 228.65 | 0.0028 |
| 4 | 47,000 | 110.906306 | 270.65 | 0 |
| 5 | 51,000 | 66.9388731 | 270.65 | -0.0028 |
| 6 | 71,000 | 3.95642043 | 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 atmospheric pressures.
Pressure 2 (P2)
This is the final atmospheric pressure used in calculating the altitude difference between two atmospheric pressures.
Altitude Difference (ΔH = H2 – H1)
This is the altitude difference when changing atmospheric pressure from P1 to P2.
Featured atmospheric pressure measurement products
Heating appliance chimney draft and barometric pressure testing using differential and absolute sensors - Very low, bi-directional chimney draft pressure and barometric pressure sensor for testing preformance of wood stoves in a research environment.
Near-atmospheric pressure transmitter for hazardous gas test chambers - Intrinsically safe pressure transmitter configured for a narrow, sub-atmospheric range to safely monitor dangerous gases in a test chamber.