POST/api/v1/e6b/density-altitude/calculateCommercial Pilot

Calculate Density Altitude

Calculates density altitude from manually provided field elevation, altimeter setting, and temperature.

Calculate density altitude from field elevation, altimeter setting, and temperature — essential for aircraft performance calculations, especially at hot/high airports.

Density altitude is the altitude at which the air density matches standard atmosphere conditions. High density altitude means thinner air, which reduces engine power, propeller efficiency, and wing lift. On a hot day at a high-elevation airport, density altitude can be thousands of feet above field elevation.

Code Examples

curl \
  -X POST \
  -H "Ocp-Apim-Subscription-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "fieldElevationFt": 748,
  "altimeterInHg": 29.92,
  "temperatureCelsius": 30
}' \
  "https://api.preflightapi.io/api/v1/e6b/density-altitude/calculate"

curl \
  -X POST \
  -H "Ocp-Apim-Subscription-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "fieldElevationFt": 748,
  "altimeterInHg": 29.92,
  "temperatureCelsius": 30
}' \
  "https://api.preflightapi.io/api/v1/e6b/density-altitude/calculate"

{
  "fieldElevationFt": 748,
  "pressureAltitudeFt": 738,
  "densityAltitudeFt": 2215,
  "temperatureCelsius": 30,
  "standardTempCelsius": 13.1,
  "tempDeviationCelsius": 16.9,
  "altimeterInHg": 29.92
}

Field Reference

densityAltitudeFt: The effective altitude for aircraft performance. In this example, the air at 748 ft elevation performs like air at 2,215 ft on a standard day — expect reduced climb, longer takeoff roll, and lower engine power.
pressureAltitudeFt: Field elevation corrected for non-standard pressure. This is what your altimeter reads when set to 29.92 inHg.
tempDeviationCelsius: How much warmer (positive) or cooler (negative) than standard temperature for this altitude. Large positive deviations significantly degrade performance.
standardTempCelsius: The standard (ISA) temperature for this elevation. Standard sea-level temp is 15°C, decreasing 2°C per 1,000 ft.

Description

Provide your own values instead of relying on METAR data. Useful for any location, for planning with forecast temperatures, or when METAR data is not available.

Response Fields

DensityAltitudeFt — the effective altitude the aircraft "feels" based on air density

PressureAltitudeFt — field elevation corrected for non-standard pressure

IsaTemperatureCelsius — the standard (ISA) temperature expected at this pressure altitude

TemperatureDeviationCelsius — how far the actual temperature deviates from ISA (positive = hotter than standard)

*Formula:*DA = PA + 120 * (OAT - ISA_temp). This does not account for humidity, local pressure patterns, or non-standard lapse rates.

Request BodyDensityAltitudeRequestDto

fieldElevationFtnumber

Field elevation in feet MSL

altimeterInHgnumber

Altimeter setting in inches of mercury (inHg)

temperatureCelsiusnumber

Temperature in degrees Celsius

Response Schema

200Returns the calculated density altitudeDensityAltitudeResponseDto

airportIdentifierstringnullable

Airport identifier (for airport-based calculations)

fieldElevationFtnumber

Field elevation in feet MSL

pressureAltitudeFtnumber

Pressure altitude in feet

densityAltitudeFtnumber

Density altitude in feet

isaTemperatureCelsiusnumber

Standard (ISA) temperature at this pressure altitude in Celsius

actualTemperatureCelsiusnumber

Actual temperature in Celsius

temperatureDeviationCelsiusnumber

Temperature deviation from ISA in Celsius

altimeterInHgnumber

Altimeter setting used in calculation (inHg)

rawMetarstringnullable

Raw METAR text for reference (for airport-based calculations)

observationTimestringnullable

METAR observation time (for airport-based calculations)

400The request parameters are invalidApiErrorResponse

codestring

Machine-readable error code (e.g., "AIRCRAFT_NOT_FOUND").

messagestring

Human-readable error message suitable for display.

detailsstringnullable

Additional error details (only included in development environment).

servicestringnullable

Name of the external service that failed (only included for 503 errors).

validationErrorsRecord<string, string[]>nullable

Field-level validation errors (only for validation failures).

timestampstring

UTC timestamp when the error occurred.

traceIdstringnullable

Correlation ID for tracing the request.

pathstringnullable

Request path that generated the error.

Hot + high = reduced performance

If density altitude exceeds your aircraft's POH limits, consider reducing payload or waiting for cooler temperatures. Many accidents occur from attempting takeoffs at high density altitude.