Case 1
- Absolute pressure
- 101325Pa
- Temperature
- 288.15K
1.2250kg/m³
Open with these valuesAir Density Calculator
1.2250kg/m³
Result: 1.2250 kg/m³Dry air at sea level and 15 °C weighs 1.225 kilograms per cubic metre — the reference figure behind every lift and drag calculation. Enter the absolute pressure in pascals and the temperature in kelvin; the density follows from the ideal gas law with the gas constant of dry air.
Worked examples
Case 2
- Absolute pressure
- 101325Pa
- Temperature
- 273.15K
1.2923kg/m³
Open with these valuesCase 3
- Absolute pressure
- 90000Pa
- Temperature
- 273.15K
1.1478kg/m³
Open with these valuesHow it's calculated
ρ = p ÷ (287.05 × T)
- StepEnter the absolute pressure in pascals, not the gauge pressure.
- StepEnter the temperature in kelvin: kelvin equals degrees Celsius plus 273.15.
- ResultRead the density of dry air in kilograms per cubic metre.
Reference table
| Pressure, temperature | Condition | Density |
|---|---|---|
| 101325, 273.15 | Sea level, 0 °C | 1.2923 |
| 101325, 288.15 | Standard atmosphere, 15 °C | 1.2250 |
| 101325, 298.15 | Sea level, 25 °C | 1.1839 |
| 100000, 300 | One bar, 26.85 °C | 1.1612 |
| 90000, 273.15 | About 1000 m, 0 °C | 1.1478 |
| 80000, 250 | About 2000 m, cold | 1.1148 |
Questions
What is the density of air at sea level?
1.225 kilograms per cubic metre in the standard atmosphere, meaning 101325 pascals and 288.15 kelvin. That is the value aviation and wind engineering use as the reference.
Do I enter degrees Celsius or kelvin?
Kelvin. Add 273.15 to a Celsius reading first, otherwise the density comes out far too high — 20 °C entered as 20 would be treated as -253 °C.
Is humid air heavier than dry air?
No, it is lighter. A water molecule weighs less than the nitrogen and oxygen it displaces, so fully saturated air at 30 °C is about one percent less dense than dry air.
Why does air density matter?
Lift, drag, fan output and engine power all scale with it. A plane needs a longer runway on a hot day at altitude because the air it flies through is thinner.
Sources and last check
Information, not professional advice.