Air Density at Constant Pressure
Reference table, calculator, and chart for air density at 1 atm across a range of temperatures
Air Density Calculator
Enter a temperature in Celsius or Kelvin to calculate air density at constant pressure:
Air Density Table
| Temperature (°C) | Density (kg/m³) |
|---|---|
| -20 | 1.395 |
| -10 | 1.341 |
| 0 | 1.293 |
| 10 | 1.247 |
| 15 | 1.225 |
| 20 | 1.204 |
| 25 | 1.184 |
| 30 | 1.165 |
| 40 | 1.127 |
| 50 | 1.092 |
| 60 | 1.058 |
| 70 | 1.026 |
| 80 | 0.995 |
| 90 | 0.966 |
| 100 | 0.946 |
Air Density Graph
About Air Density at Constant Pressure
Air density is the mass of air per unit volume, typically expressed in kilograms per cubic meter (kg/m³). It is a fundamental property in thermodynamics, fluid mechanics, HVAC engineering, and aerospace applications, as it directly affects airflow, heat transfer, energy calculations, and aerodynamic performance.
Standard Reference Value
At 15°C (288.15 K) and 1 atm pressure, the density of dry air is approximately 1.225 kg/m³. This value serves as a standard reference for engineering calculations and scientific analysis.
Factors Affecting Air Density
Air density varies primarily with temperature, pressure, and humidity. At standard atmospheric pressure (1 atm) and dry air conditions, air density decreases with increasing temperature. Understanding these variations is crucial for:
- Thermodynamics: Accurate calculation of energy, heat capacity, and enthalpy.
- Fluid Mechanics: Modeling airflow in ducts, fans, turbines, and compressors.
- HVAC Design: Sizing ventilation systems, air conditioning, and heating systems.
- Aerospace & Aerodynamics: Computing lift, drag, and aircraft performance metrics.
- Environmental Engineering: Simulating pollutant dispersion, air quality, and ventilation efficiency.
How Engineers Use Air Density
Engineers and scientists use air density in combination with other atmospheric properties—such as temperature, pressure, specific gas constant, and humidity—to accurately model air behavior in flow systems, turbines, compressors, ventilation systems, and environmental simulations.
Using reliable air density data ensures precision in thermodynamic calculations, HVAC design, aerodynamic simulations, and energy efficiency analysis, making it an indispensable reference for engineering and scientific applications.