Density Altitude Formula and Conversion Calculations
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Our Density Altitude Calculator Formulas
The Density Altitude Formula and Calculations in Detail
Our Density Altitude Calculator uses complex and precise calculations from weather.gov by Tim Brice and Todd Hall, but provides a modern mobile friendly user interface. The process involves several steps, starting with the calculation of the virtual temperature. It involves more steps than pilots generally want to do by hand and considers additional factors like humidity and precise pressure measurements. This method is more accurate but also more complex, making it better suited for precise applications where detailed environmental data is available. Below we explain all of the formulas and calculations used in our calculator in 3 sections:
Given the user provided air temperature, a station pressure (), and a dewpoint temperature. The density altitude calculation is quite complex. Before calculating the density altitude, the virtual temperature must be calculated first. To perform all the calculation for the density altitude calculation, the air temperature must be in units of Kelvin, the station pressure must be in units of inches of mercury (inHg) and millibars (), and the dewpoint temperature must be in units of degrees Celsius.
To calculate the virtual temperature, a vapor pressure (e) must be calculated first using the equation below.
then using the station pressure in units of millibars, the virtual temperature can be calculated:
The virtual temperature answer will be in units of Kelvinand needs to converted to Rankineto calculate the density altitude. To see how to convert Kelvin to Rankine. Finally, the density altitude can be calculated. Using the virtual temperature in units of Rankineand station pressure in inches of mercury)
Formulas to convert the temperature and pressure are below.
Temperature Conversion Formulas for Density Altitude Calculation
To convert between Fahrenheit and degrees Celsius :
Where:
is temperature in Celsius
is temperature in Fahrenheit
To convert between degrees Fahrenheit ( ) and Kelvin (K):
Where:
is temperature in Fahrenheit
is temperature in Kelvin
To convert between degrees Fahrenheit ( ) and Rankine (R):
Where:
is temperature in Fahrenheit
is temperature Rankine
To convert between degrees Celsius ) and Kelvin (K):
Where:
is temperature in Celsius
is temperature in Kelvin
To convert between degrees ( ∘C ) and Rankine (R):
Where:
is temperature in Celsius
is temperature in Rankine
To convert between degrees Kelvin (K) and Rankine (R):
Where:
is temperature in Kelvin
is temperature in Rankine
Pressure Conversion Formulas for Density Altitude Calculation
Here are some useful conversion formulas for atmospheric pressure given in a variety of formats.
To convert between inches of mercury ( ) and millimeters of mercury (mmHg) or Torr
Use these formulas:
To convert between inches of mercury ( ) and millibars or hectopascals :
Use these formulas:
Convert between inches of mercury ( ) and kilopascals
Use these formulas to convert from inHg to kPa:
Convert between inches of mercury ( ) and pounds per square inch ( ):
Use these formulas to convert from inHg to psi:
Convert between torr or millimeters of mercury ( ) and millibars ) or hectopascals :
Use these formulas to convert from mmHg and mb or hPa to psi:
Convert between torr or millimeters of mercury ( ) and kilopascals ):
Use these formulas to convert from mmHg and kPa to psi:
Convert between torr or millimeters of mercury ( ) and kilopascals )
Use these formulas:
Convert between torr or millimeters of mercury ) and pounds per square inch ( )
Use these formulas:
Convert between millibars or hectopascals and kilopascals
Use these formulas:
Convert between millibars or hectopascals and pounds per square inch ( )
Use these formulas:
Convert between kilopascals and pounds per square inch ( )
Use these formulas to convert from kPa to psi:
Convert between standard atmosphere ( ) and millimeters of mercury ( ) or torr
Use these formulas:
Convert between standard atmosphere ( ) and inches of mercury (inHg)
Use these formulas:
Convert between standard atmosphere ( ) and pounds per square inch ( )
Use these formulas to convert from atm to psi:
Convert between standard atmosphere ( ) and millibars ) or hectopascals (hPa)
Use these formulas:
Convert between standard atmosphere ( ) and kilopascals
Use these formulas to convert from atm to kPa: