Calculator How to Calculate Density Altitude

Density altitude is a critical concept in aviation, as it indicates the altitude at which the aircraft "feels" like it is flying due to the density of the air. High density altitude can affect aircraft performance, reducing engine power, thrust, and lift. Here's how to calculate density altitude.

Factors Affecting Density Altitude:

1. Pressure Altitude: The altitude corrected for non-standard pressure.
2. Outside Air Temperature (OAT): The current temperature at your altitude.
3. Humidity: This can also affect density altitude, but for simplicity, it's often not included in basic calculations.

Step-by-Step Calculation:

1. Calculate Pressure Altitude:

   • Use the standard pressure setting (29.92 inches of Mercury or 1013.25 hPa).
   • Formula: $$\text{Pressure Altitude} = \text{Elevation} + (29.92 - \text{Current Altimeter Setting}) \times 1000$$

2. Calculate Density Altitude:

   • Use the temperature deviation from the standard atmosphere.
   • Formula: $$\text{Density Altitude} = \text{Pressure Altitude} + [120 \times (\text{OAT} - \text{ISA Temperature at Elevation})]$$
   • ISA (International Standard Atmosphere) temperature at sea level is 15°C and decreases by approximately 2°C for every 1000 feet of altitude.

Example Calculation:

1. Elevation: 5,000 feet
2. Current Altimeter Setting: 30.12 inHg
3. OAT: 25°C

Step-by-step Calculation:

1. Calculate Pressure Altitude:

   $$\text{Pressure Altitude} = 5000 + (29.92 - 30.12) \times 1000$$ $$\text{Pressure Altitude} = 5000 + (-0.20) \times 1000 = 5000 - 200 = 4800 \text{ feet}$$

2. Calculate ISA Temperature at Elevation:

   $$\text{ISA Temperature} = 15 - (2 \times \frac{5000}{1000}) = 15 - 10 = 5°C$$

3. Calculate Density Altitude:

   $$\text{Density Altitude} = 4800 + [120 \times (25 - 5)]$$ $$\text{Density Altitude} = 4800 + [120 \times 20] = 4800 + 2400 = 7200 \text{ feet}$$

Density Altitude Calculator

Elevation (feet):

Current Altimeter Setting (inHg):

Outside Air Temperature (°C):