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   Altimetry   More precise than your average e6b:
Highlight field, type in the unit and get the conversion for all other units

Introduction

  
 

Altimetry, Airspeed, and Performance with 12 essential aviation calculators

Welcome to your all-in-one suite of essential aviation calculators, designed for pilots, students, and flight instructors. This page features a powerful set of tools to solve for critical flight and atmospheric variables. Our calculators cover:
     -  Performance: True Airspeed (TAS), Equivalent Airspeed (EAS), and Mach Number
     -  Altitude: Pressure Altitude, Density Altitude, True Altitude, and Cloud Base
     -  Altimeter & Pressure: QNH (altimeter setting), QFE (zero height setting), and Altitude Correction
     -  Temperature: Temperature Conversion and Temperature Rise
Each tool supports a full range of unit conversions for international use. A powerful "inverse" calculation feature is built into every calculator: simply leave any single field blank, and the tool will solve for it. This makes it perfect for flexible flight planning, "what-if" scenarios, or for instructors creating training problems with specific answers.

  

Page Table of Contents

 Use these links to go directly to desired calculator
  Temperature Conversion Cloud Base
  Altitude Correction for Pressure Altitude True Altitude
  Pressure Altitude True Airspeed
  QNH (altimeter setting) Temperature Rise
  QFE (zero height setting) Mach Number
  Density Altitude Equivalent Airspeed

Temperature
Conversion

  
Temperature
      [oF]   [oC]     [oR]    [K]

    Enter a number in any box and get all the remaining box's results

Altitude Correction for
Pressure Altitude

  
Altimeter Setting
     [inHg]    [HPa] or [mbar]  
Altitude Correction
    [ft]  [m]  

     Enter the altimeter setting or altitude correction  

Pressure
Altitude

  
Calibrated Altitude
    [ft]
  [m]
Altimeter Setting (QNH)
    [inHg]
  [HPa] or [mbar]
Pressure Altitude
     [ft]   [m]
                            or
Absolute Atmospheric Pressue
     [inHg]    [HPa] or [mbar]  
Pressure Altitude
    [ft]  [m]  

    If using the top portion (1st calculator), enter any two fields (i.e. Altitude, Altimeter Setting or Pressure Altitude) then
    press "Eval" on any remaining field for that field's result. If using the lower portion (2nd calculator), enter the Absolute
    Atmospheric Pressure or Pressure Altitude and see the remaining field be calculated.

    QNH is a term not commonly used in the United States but used in many other countries. It is the altimeter setting setting
    such that the altimeter reads altitude above mean sea level at the airport level. In the U.S. this is referred to as the altimeter
    setting and is usually given by ATC (Air Traffic Control) or the airport ATIS (Airport Terminal Information Service)
    among other sources.

    Note 1: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other two rows when the Eval button of that row is pressed.

    Note 2: If you don't have Calibrated Altitude (CA) use Indicated Altitude.

    Note 3: Absolute Atmospheric Pressure is also refered to as Absolute Barometric Pressure.

QNH (Altimeter Setting)

  
Airport Altitude
    [ft]   [m]
Pressure Altitude at Airport
    [ft]   [m]
Altimeter Setting (QNH)
     [inHg]   [HPa] or [mbar]

    Enter any two fields (i.e. Altitude, Altimeter Setting or Pressure Altitude)
    then press "Eval" on any remaining field for that field's result

    QNH is a term not commonly used in the United States but used in many other countries. It is the altimeter setting
    such that the altimeter reads altitude above mean sea level at the airport level. In the U.S. this is referred to as the altimeter
    setting and is usually given by ATC (Air Traffic Control) or the airport ATIS (Airport Terminal Information Service) among
    other sources. Pressure Altitude is the altitude the altimeter reads when set to the QNE setting 1013.25 hPa or
    approximately 29.92 inHg. QNE is also a term used more internationally but denotes the altimeter setting to obtain the
    pressure altitude reading.

    Note that it does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other two rows when the Eval button of that row is pressed.

QFE
('Zero' Altimeter Setting)

  
Pressure Altitude at Airport
    [ft]   [m]  
QFE Setting
     [inHg]   [HPa] or [mbar]  

     Enter the pressure altitude at airport or the QFE setting  
    QFE is a term also not commonly used in the United States but referred to in many other countries. In practice it is not used
    very much but it is useful to know of it's existence. It is the altimeter setting such that the altimeter reads zero height at the
    airport level. Not to be confused with pressure altitude, which is the altitude the altimeter reads when set to the QNE setting
    1013.25 hPa or approximately 29.92 inHg. QNE is also a term used more internationally but denotes the altimeter setting to
    obtain the pressure altitude reading. Note altimeters will have a limit at which the setting can be adjusted.

Density
Altitude

  
Pressure Altitude
  [ft]
[m]
Temperature
  [oF]
[oC] 
Density Altitude
     [ft] [m]

    Enter any two fields (i.e. Pressure Altitude, Temperature or Density Altitude) then press "Eval" on any remaining field
    for that field's result
    Note that it does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other two rows when the Eval button of that row is pressed.

    RELATED WEBSITES:
     Wahiduddin's Website (Interesting website with a very thorough explanation of density altitude)
           Link to a very complete density altitude calculator and discussion of the effects of humidity
 

Cloud
Base

  
  Main Variables
Air Temperature at Ground Level
  [oF]
[oC]
Dewpoint at Ground Level
  [oF]
[oC] 
Cloud Base Altitude Above Ground Level (AGL)
     [ft] [m]

Correlated Variables
Temperature/Dewpoint Spread
  [oF]
[oC]
Estimated Freezing Level Above Ground
  [ft]
[m]
Estimated Temperature at Cloud Base
  [oF]
[oC]
 
Enter any two fields (i.e. Air Temperature at Ground Level, Dewpoint at Ground Level or Cloud Base Altitude Above Ground Level) then press "Eval" on any remaining field for that field's result. Other useful information that can be derived will also be displayed on the "Correlated Variables" section.
Note that it does not matter the order that you enter the rows. The remaining row (field) will be calculated based on the values of the other two rows when the Eval button of that row is pressed.		  

True
Altitude

  
Pressure Altitude (PA)
     [ft]   [m]
True Air Temperature (T)
     [oF]   [oC]
Calibrated Altitude (CA)
     [ft]   [m]
Station Altitude
     [ft]   [m]
True Altitude (TA)
     [ft]   [m]
          or    
Pressure Altitude (PA)
     [ft]   [m]
True Air Temperature (T)
     [oF]   [oC]
Altimeter Setting (QNH)
     [inHg]   [HPa] or [mbar]
Station Altitude
     [ft]   [m]
True Altitude (TA)
     [ft]   [m]
          or    
Calibrated Altitude (CA)
     [ft]   [m]
True Air Temperature (T)
     [oF]   [oC]
Altimeter Setting (QNH)
     [inHg]   [HPa] or [mbar]
Station Altitude
     [ft]   [m]
True Altitude (TA)
     [ft]   [m]

    Enter any four fields then press "Eval" on any remaining field for that field's result. True Altitude computations are
    inherently imprecise, please be cautious, particularly when extrapolating beyond typical conditions.     Note 1: If you don't have the Station Altitude set it to zero

    Note 2: If you don't have Calibrated Altitude (CA) use Indicated Altitude

     Note 3: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other rows when the Eval button of that row is pressed.

    Note 4: True Air Temperature (T) is also referred to as Outside Air Temperature (OAT) or Static Air Temperature (SAT).
     True Air Temperature (T) is sometimes abbreviated (TAT). It is NOT to be confused to Total Air Temperature also
     abbreviated (TAT) which is the same as Indicated Temperature (IAT) or Ram Air Temperatures (RAT).

True
Airspeed
  Correct for compressibility (more precise at high airspeeds) and supersonic speeds.
Note: Most E6B flight computers do not adequately factor compressibility at high airspeeds and supersonic flight regime. Therefore if you are trying to compare the results from this calculator with an E6B and most flight computers you should uncheck this box.
  Main Variables
Pressure Altitude (PA)     [ft]   [m]
Recovery Coefficient (CT)    
Indicated Air Temperature (IAT)     [oF]   [oC]
Calibrated Airspeed (CAS)     [knots]   [Km/h]
True Airspeed (TAS)     [knots]   [Km/h]
 
  Correlated Variables
True Air Temperature (T)       [oF]   [oC]
Mach (M)      
Pitot Tube Impact Pressure (qc)       [inHg]   [HPa] or [mbar]
Static Pressure (P)       [inHg]   [HPa] or [mbar]
Pitot Tube Total Pressure (Pt=qc+P)       [inHg]   [HPa] or [mbar]
Speed of Sound (CS)       [knots]   [Km/h]
Temperature Rise (ΔT=IAT-T)       [ΔoF]   [ΔoC]
                            or
  Main Variables
Pressure Altitude (PA)     [ft]   [m]
Calibrated Airspeed (CAS)     [knots]   [Km/h]
True Air Temperature (T)     [oF]   [oC]
True Airspeed (TAS)     [knots]   [Km/h]
 
  Correlated Variables
Mach (M)      
Pitot Tube Impact Pressure (qc)       [inHg]   [HPa] or [mbar]
Static Pressure (P)       [inHg]   [HPa] or [mbar]
Pitot Tube Total Pressure (Pt=qc+P)       [inHg]   [HPa] or [mbar]
Speed of Sound (CS)       [knots]   [Km/h]
Indicated Air Temperature (IAT) if CT=1.0       [oF]   [oC]

    Enter any four fields in white on the upper portion or three fields in white on the lower portion then press "Eval" on
    that portion for any remaining field for that field's result. True Airspeed computations are somewhat imprecise, please be
    cautious, particularly when extrapolating beyond typical conditions. When calculating the Recovery Coefficient there is a
    vary narrow range of solutions. The model used takes into consideration compressibility and may be used for speeds
    beyond Mach 1. Correlated Variables display other information and are calculated from results once Eval has been pressed.

    Note 1: If you don't know the recovery coefficient set it to 1.0.

    Note 2: If you don't have the Calibrated Airspeed (CAS) use Indicated Airespeed (IAS) in place of CAS.

    Note 3: True Air Temperature (T) is also referred to as Outside Air Temperature (OAT) or Static Air Temperature (SAT).
     True Air Temperature (T) is sometimes abbreviated TAT. It is NOT to be confused to Total Air Temperature also
     abbreviated TAT which is the same as Indicated Temperature (IAT) or Ram Air Temperatures (RAT).

    Note 4: Indicated Temperature (IAT) is also referd to as Total Air Temperature (TAT) or Ram Air Temperature (RAT).
     Total Air Temperature (TAT) is NOT to be confused to True Air Temperature also abbreviated TAT (see note 2 above)

    Note 5: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other rows when the Eval button of that row is pressed.

Temperature
Rise

  
True Airspeed (TAS)     [knots]   [Km/h]
Recovery Coefficient (CT)    
Temperature Rise (ΔT=IAT-T)      [ΔoF]   [ΔoC]

    Enter any two fields then press "Eval" on any remaining field for that field's result. When calculating the Recovery Coefficient
    there is a vary narrow range of solutions. The model used takes into consideration compressibility and may be used for speeds
    beyond Mach 1. To calculate True Air Temperature (T) use T=IAT-ΔT. Where IAT is the Indicated Air Temperature and ΔT is
    the Temperature Rise.

   Note 1: If you don't know the Recovery Coefficient (CT) set it to 1.0.

   Note 2: True Air Temperature (T) is also referred to as Outside Air Temperature (OAT) or Static Air Temperature (SAT).
     True Air Temperature (T) is sometimes abbreviated TAT. It is NOT to be confused to Total Air Temperature also
     abbreviated TAT which is the same as Indicated Temperature (IAT) or Ram Air Temperatures (RAT).

    Note 3: Indicated Air Temperature (IAT) is also referd to as Total Air Temperature (TAT) or Ram Air Temperature (RAT).
     Total Air Temperature (TAT) is NOT to be confused to True Air Temperature also abbreviated TAT (see note 2 above)

    Note 4: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other rows when the Eval button of that row is pressed.

Mach
Number
  Correct for compressibility (more precise at high airspeeds) and supersonic speeds.
Note: Most E6B flight computers do not adequately factor compressibility at high airspeeds and supersonic flight regime. Therefore if you are trying to compare the results from this calculator with an E6B and most flight computers you should uncheck this box.
  Main Variables
Pressure Altitude (PA)     [ft]   [m]
Calibrated Airspeed (CAS)     [knots]   [Km/h]
Mach Number (M)     
 
  Correlated Variables
Pitot Tube Impact Pressure (qc)       [inHg]   [HPa] or [mbar]
Static Pressure (P)       [inHg]   [HPa] or [mbar]
Pitot Tube Total Pressure (Pt=qc+P)       [inHg]   [HPa] or [mbar]
                            or
  Main Variables
True Airspeed (TAS)     [knots]   [Km/h]
Recovery Coefficient (CT)    
Indicated Air Temperature (IAT)     [oF]   [oC]
Mach Number (M)    
 
  Correlated Variables
True Air Temperature (T)       [oF]   [oC]
Speed of Sound (CS)       [knots]   [Km/h]
Temperature Rise (ΔT=IAT-T)       [ΔoF]   [ΔoC]
                            or
   Main Variables
True Airspeed (TAS)     [knots]   [Km/h]
True Air Temperature (T)   [oF]   [oC]
Mach Number (M)    
 
  Correlated Variables
Speed of Sound (CS)       [knots]   [Km/h]
Indicated Air Temperature (IAT) if CT=1.0       [oF]   [oC]

    Enter any two fields in white on the upper portion, three in the middle, or two fields on the lower portion then press "Eval"
    on that portion for any remaining field for that field's result. Other useful information that can be derived will also be displayed
    on the "Correlated Variables" section.

    Note 1: If you don't know the recovery coefficient set it to 1.0.

    Note 2: Indicated Air Temperature (IAT) is also referd to as Total Air Temperature (TAT) or Ram Air Temperature (RAT).
     Total Air Temperature (TAT) is NOT to be confused to True Air Temperature also abbreviated TAT. True Air
     Temperature (TAT) or (T) is also referred to as Outside Air Temperature (OAT) or Static Air Temperature (SAT)

    Note 3: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other rows when the Eval button of that row is pressed.

Equivalent
Airspeed
  Correct for compressibility (more precise at high airspeeds) and supersonic speeds.
Note: Most E6B flight computers do not adequately factor compressibility at high airspeeds and supersonic flight regime. Therefore if you are trying to compare the results from this calculator with an E6B and most flight computers you should uncheck this box.
  Main Variables
Pressure Altitude (PA)     [ft]   [m]
True Air Temperature (T)     [oF]   [oC]
True Airspeed (TAS)      [knots]   [Km/h]
Equivalent Airspeed (EAS)     [knots]   [Km/h]
 
  Correlated Variables
Calibrated Airspeed (CAS)       [knots]   [Km/h]
Mach (M)      
Pitot Tube Impact Pressure (qc)       [inHg]   [HPa] or [mbar]
Static Pressure (P)       [inHg]   [HPa] or [mbar]
Pitot Tube Total Pressure (Pt=qc+P)       [inHg]   [HPa] or [mbar]
Speed of Sound (CS)       [knots]   [Km/h]

     Enter any three fields in white then press "Eval" on any remaining field for that field's result. Other useful information that
     can be derived will also be displayed on the "Correlated Variables" section.

    Note 1: True Air Temperature (T) is also referred to as Outside Air Temperature (OAT) or Static Air Temperature (SAT).
     True Air Temperature (T) is sometimes abbreviated TAT. It is NOT to be confused to Total Air Temperature also
     abbreviated TAT which is the same as Indicated Temperature (IAT) or Ram Air Temperatures (RAT).

    Note 2: It does not matter the order that you enter the rows. The remaining row (field) will be
    calculated based on the values of the other rows when the Eval button of that row is pressed.


   
 
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