Air Density Calculator
Calculate air density based on temperature, pressure, and humidity using atmospheric physics
Calculate Air Density
Atmospheric pressure (standard: 1013.25 hPa)
Ambient air temperature
Select air type for calculation
Relative humidity percentage (0-100%)
Air Density Results
Pressure: 1013.25 hPa
Temperature: 15.0°C (288.1 K)
Vapor Pressure: 8.53 hPa
Dry Air Pressure: 1004.72 hPa
Standard Density: 1.225 kg/m³
Interpretation: Standard atmospheric conditions
Altitude Effects on Air Density
Example Calculation
Standard Conditions
Pressure: 1013.25 hPa
Temperature: 15°C (288.15 K)
Humidity: 50% RH
Air Type: Moist air
Calculation Steps
1. Saturation pressure: 17.04 hPa
2. Vapor pressure: 8.52 hPa
3. Dry air pressure: 1004.73 hPa
4. Dry air density: 1.216 kg/m³
5. Vapor density: 0.006 kg/m³
Total density: 1.222 kg/m³
Standard Atmospheric Conditions
STP (Standard Temperature & Pressure)
0°C, 1013.25 hPa
Density: 1.275 kg/m³
ISA (International Standard Atmosphere)
15°C, 1013.25 hPa
Density: 1.225 kg/m³
NTP (Normal Temperature & Pressure)
20°C, 1013.25 hPa
Density: 1.204 kg/m³
Air Properties
Dry air: ~78% N₂, ~21% O₂, ~1% Ar
Water vapor reduces air density (H₂O lighter than N₂/O₂)
Temperature increase decreases density
Pressure increase increases density
Altitude increase decreases density
Understanding Air Density
What is Air Density?
Air density (ρ) is the mass of air per unit volume, typically measured in kg/m³. It represents how tightly packed air molecules are in a given space and varies significantly with temperature, pressure, and humidity.
Why is it Important?
- •Aircraft performance and lift calculations
- •Meteorology and weather prediction
- •HVAC system design and efficiency
- •Wind turbine performance optimization
Calculation Formula
ρ = (pd/RdT) + (pv/RvT)
- ρ: Air density (kg/m³)
- pd: Dry air pressure (Pa)
- pv: Water vapor pressure (Pa)
- Rd: Dry air gas constant (287.058 J/kg·K)
- Rv: Water vapor gas constant (461.495 J/kg·K)
- T: Absolute temperature (K)
Note: For dry air, only the first term is used. Water vapor reduces overall density.
Factors Affecting Air Density
Temperature
Higher temperature → Lower density. Air molecules move faster and spread out more at higher temperatures.
Pressure
Higher pressure → Higher density. More air molecules are packed into the same volume.
Humidity
Higher humidity → Lower density. Water vapor (H₂O) is lighter than dry air molecules (N₂, O₂).