• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
SensorsONE

SensorsONE

  • Products
  • Search
  • Contact

US Standard Atmosphere Altitude and Pressure Calculator

Calculate Altitude & Pressure Parameters
Select Answer Mode
Altitude (H) [?]
Pressure (P) [?]
Altitude 1 (H1) [?]
Altitude 2 (H2) [?]
Pressure Difference (ΔP = P2 - P1) [?]
Pressure 1 (P1) [?]
Pressure 2 (P2) [?]
Altitude Difference (ΔH = H2 - H1) [?]

Click save settings to reload page with unique web page address for bookmarking and sharing the current tool settings

✕ clear 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.
  • 700 to 1100 millibar scaled 4 to 20mA output pressure sensor for barometric pressure measurement - 4-20mA output transmitter for monitoring barometric pressure from 700 to 1100 mbar absolute.

Related Tools

  • ICAO Standard Atmosphere Altitude and Pressure Calculator
  • Pressure unit conversion
  • Height unit conversion

Contents

Toggle
  • User Guide
    • Formulas
      • Symbols
      • Atmospheric Layer Constants
    • Altitude (H)
    • Pressure (P)
    • Altitude 1 (H1)
    • Altitude 2 (H2)
    • Pressure Difference (ΔP = P2 – P1)
    • Pressure 1 (P1)
    • Pressure 2 (P2)
    • Altitude Difference (ΔH = H2 – H1)

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

  • DCT531P RS485 Modbus RTU Flush Pressure Sensor - RS485 Modbus RTU serial interface pressure sensor with exposed all welded stainless steel 316L flush diaphragm in ranges from 100mb up to 40 bar gauge or absolute.
  • Baroli 05 Industrial Digital Pressure Gauge - Digital pressure gauge with ranges from 0.6 bar (9 psi) up to 600 bar (9000 psi) gauge or absolute and an accuracy of 0.25% full scale.

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

  • 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.
  • Marine approved atmospheric pressure sensor - Marine-approved pressure sensor for atmospheric pressure measurement on ships. 4-20mA output, 800-1200mbar range.

Primary Sidebar

Tools

  • Unit Converters
  • Pressure
  • Liquid Level
  • Temperature & Heat
  • Electrical & Electromagnetic
  • Flow
  • Force, Load & Torque
  • Mass & Weight
  • Dimensions
  • Density
  • Time & Frequency
  • Speed & Acceleration
  • Energy & Power
  • Sensors & Instrumentation
  • Shapes
  • Movement & Motion
  • Travel & Transportation
  • Pricing & Quantities
  • Chemical Quantities
  • Health & Fitness

Tool Feedback

Please provide feedback on using this US Standard Atmosphere Altitude and Pressure Calculator.

Wirelessly Measure & Log Pressure

Use this battery powered wireless pressure sensor to transmit readings to a receiver connected to USB, RS485, RS232, cellular network or analog output

Use this battery powered wireless pressure sensor to transmit readings to a receiver connected to USB, RS485, RS232, cellular network or analog output
By clicking "OK" or continuing to use this website you are providing your consent to use cookies as described in our Privacy Policy

© 2025 SensorsONE Ltd, all rights reserved

  • Home
  • Products
  • Tools
  • Legal
  • Contact